Biocompatibility of biomaterials for nanoencapsulation: Current approaches
- Witika, Bwalya A, Makoni, Pedzisai A, Matafwali, Scott K, Chabalenge, Billy, Mwila, Chiluba, Kalungia, Aubrey C, Nkanga, Christian I, Bapolisi, Alain M, Walker, Roderick B
- Authors: Witika, Bwalya A , Makoni, Pedzisai A , Matafwali, Scott K , Chabalenge, Billy , Mwila, Chiluba , Kalungia, Aubrey C , Nkanga, Christian I , Bapolisi, Alain M , Walker, Roderick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183289 , vital:43939 , xlink:href="https://doi.org/10.3390/nano10091649"
- Description: Nanoencapsulation is an approach to circumvent shortcomings such as reduced bioavailability, undesirable side effects, frequent dosing and unpleasant organoleptic properties of conventional drug delivery systems. The process of nanoencapsulation involves the use of biomaterials such as surfactants and/or polymers, often in combination with charge inducers and/or ligands for targeting. The biomaterials selected for nanoencapsulation processes must be as biocompatible as possible. The type(s) of biomaterials used for different nanoencapsulation approaches are highlighted and their use and applicability with regard to haemo- and, histocompatibility, cytotoxicity, genotoxicity and carcinogenesis are discussed.
- Full Text:
- Date Issued: 2020
- Authors: Witika, Bwalya A , Makoni, Pedzisai A , Matafwali, Scott K , Chabalenge, Billy , Mwila, Chiluba , Kalungia, Aubrey C , Nkanga, Christian I , Bapolisi, Alain M , Walker, Roderick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183289 , vital:43939 , xlink:href="https://doi.org/10.3390/nano10091649"
- Description: Nanoencapsulation is an approach to circumvent shortcomings such as reduced bioavailability, undesirable side effects, frequent dosing and unpleasant organoleptic properties of conventional drug delivery systems. The process of nanoencapsulation involves the use of biomaterials such as surfactants and/or polymers, often in combination with charge inducers and/or ligands for targeting. The biomaterials selected for nanoencapsulation processes must be as biocompatible as possible. The type(s) of biomaterials used for different nanoencapsulation approaches are highlighted and their use and applicability with regard to haemo- and, histocompatibility, cytotoxicity, genotoxicity and carcinogenesis are discussed.
- Full Text:
- Date Issued: 2020
Biological control of water lettuce, Pistia stratiotes L., facilitates macroinvertebrate biodiversity recovery: a mesocosm study
- Coetzee, Julie A, Langa, Susana D, Motitsoe, Samuel N, Hill, Martin P
- Authors: Coetzee, Julie A , Langa, Susana D , Motitsoe, Samuel N , Hill, Martin P
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423967 , vital:72112 , xlink:href="https://doi.org/10.1007/s10750-020-04369-w"
- Description: Floating aquatic weed infestations have negative socio-economic and environmental consequences to the ecosystems they invade. Despite the long history of invasion by macrophytes, only a few studies focus on their impacts on biodiversity, while the ecological benefits of biological control programmes against these species have been poorly quantified. We investigated the process of biotic homogenization following invasion by Pistia stratiotes on aquatic biodiversity, and recovery provided by biological control of this weed. Biotic homogenization is the increased similarity of biota as a result of introductions of non-native species. The study quantified the effect of P. stratiotes, and its biological control through the introduction of the weevil, Neohydronomus affinis on recruitment of benthic macroinvertebrates to artificial substrates. Mats of P. stratiotes altered the community composition and reduced diversity of benthic macroinvertebrates in comparison to an uninvaded control. However, reduction in percentage cover of the weed through biological control resulted in a significant increase in dissolved oxygen, and recovery of the benthic macroinvertebrate community that was comparable to the uninvaded state. This highlights the process of homogenization by an invasive macrophyte, providing a justification for sustained ecological and restoration efforts in the biological control of P. stratiotes where this plant is problematic.
- Full Text:
- Date Issued: 2020
- Authors: Coetzee, Julie A , Langa, Susana D , Motitsoe, Samuel N , Hill, Martin P
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423967 , vital:72112 , xlink:href="https://doi.org/10.1007/s10750-020-04369-w"
- Description: Floating aquatic weed infestations have negative socio-economic and environmental consequences to the ecosystems they invade. Despite the long history of invasion by macrophytes, only a few studies focus on their impacts on biodiversity, while the ecological benefits of biological control programmes against these species have been poorly quantified. We investigated the process of biotic homogenization following invasion by Pistia stratiotes on aquatic biodiversity, and recovery provided by biological control of this weed. Biotic homogenization is the increased similarity of biota as a result of introductions of non-native species. The study quantified the effect of P. stratiotes, and its biological control through the introduction of the weevil, Neohydronomus affinis on recruitment of benthic macroinvertebrates to artificial substrates. Mats of P. stratiotes altered the community composition and reduced diversity of benthic macroinvertebrates in comparison to an uninvaded control. However, reduction in percentage cover of the weed through biological control resulted in a significant increase in dissolved oxygen, and recovery of the benthic macroinvertebrate community that was comparable to the uninvaded state. This highlights the process of homogenization by an invasive macrophyte, providing a justification for sustained ecological and restoration efforts in the biological control of P. stratiotes where this plant is problematic.
- Full Text:
- Date Issued: 2020
Biological control potential of ectomycorrhizal fungi against Fusarium circinatum on Pinus patula seedlings
- Chartier FitzGerald, Veronique, Dames, Joanna F, Hawley, Grant L
- Authors: Chartier FitzGerald, Veronique , Dames, Joanna F , Hawley, Grant L
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425960 , vital:72302 , xlink:href="https://doi.org/10.1080/09583157.2020.1771542"
- Description: The South Africa forestry industry, covering ∼1.3 million hectares, is dependent on exotic pine and Eucalyptus species. Nursery seedlings are not inoculated with ectomycorrhizal (ECM) fungi or other beneficial microbes. Fusarium circinatum is an economically important pathogen affecting seedling survival. The purpose of this investigation was to assess the effects of ectomycorrhizal fungal inoculation on Pinus patula seedling growth and resistance to the fungal pathogen F. circinatum. Explants from ECM basidiocarps, collected from Pinus stands, were plated onto MMN medium to obtain isolates that were then verified via DNA extraction and PCR amplification and sequencing of the ITS rDNA region. These isolates were identified as Boletus edulis f. reticulatus, Lactarius quieticolor, Suillus granulatus and an unknown Suillus species. P. patula growth in the presence of the pathogen F. circinatum was significantly increased and promoted by the L. quieticolor and Suillus isolates. Preventative inoculation of seedlings in the nursery using these isolates would ensure the production of stronger, healthier plants that would be more resistant to F. circinatum infection, increasing survival in the plantation.
- Full Text:
- Date Issued: 2020
- Authors: Chartier FitzGerald, Veronique , Dames, Joanna F , Hawley, Grant L
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425960 , vital:72302 , xlink:href="https://doi.org/10.1080/09583157.2020.1771542"
- Description: The South Africa forestry industry, covering ∼1.3 million hectares, is dependent on exotic pine and Eucalyptus species. Nursery seedlings are not inoculated with ectomycorrhizal (ECM) fungi or other beneficial microbes. Fusarium circinatum is an economically important pathogen affecting seedling survival. The purpose of this investigation was to assess the effects of ectomycorrhizal fungal inoculation on Pinus patula seedling growth and resistance to the fungal pathogen F. circinatum. Explants from ECM basidiocarps, collected from Pinus stands, were plated onto MMN medium to obtain isolates that were then verified via DNA extraction and PCR amplification and sequencing of the ITS rDNA region. These isolates were identified as Boletus edulis f. reticulatus, Lactarius quieticolor, Suillus granulatus and an unknown Suillus species. P. patula growth in the presence of the pathogen F. circinatum was significantly increased and promoted by the L. quieticolor and Suillus isolates. Preventative inoculation of seedlings in the nursery using these isolates would ensure the production of stronger, healthier plants that would be more resistant to F. circinatum infection, increasing survival in the plantation.
- Full Text:
- Date Issued: 2020
Biomes, geology and past climate drive speciation of laminate-toothed rats on South African mountains (Murinae: Otomys)
- Taylor, Peter J, Kearney, Theresa, Dalton, Desire L, Chakona, Gamuchirai, Kelly, Christopher M R, Barker, Nigel P
- Authors: Taylor, Peter J , Kearney, Theresa , Dalton, Desire L , Chakona, Gamuchirai , Kelly, Christopher M R , Barker, Nigel P
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425481 , vital:72249 , xlink:href="https://doi.org/10.1093/zoolinnean/zlz134"
- Description: Mitochondrial DNA sequences (1137 bp) of the cytochrome b gene and craniodental and craniometric data were used to investigate the evolutionary relationships of six putative rodent taxa of Otomys (family Muridae: subfamily Murinae: tribe Otomyini) co-occurring in the Western Cape and Eastern Cape provinces of South Africa. Phylogenetic analysis of 20 new sequences together with craniodental and craniometric characters of 94 adult skulls reveal the existence of a unique lineage of Otomys cf. karoensis (named herein Otomys willani sp. nov.) from the Sneeuberg Centre of Floristic Endemism in the southern Drakensberg Mountain Range. Craniometric analysis distinguished O. karoensis from O. willani and identified a further four localities in the range of the latter species. We document southern range extensions of both Sloggett’s ice rat, Otomys sloggetti, and the vlei rat Otomys auratus to the Sneeuberg Mountain Range, in addition to appreciable genetic divergence between Sneeuberg and southern and central Drakensberg populations of O. sloggetti. Our results demonstrate parallel patterns of cryptic speciation in two co-occurring species complexes (Otomys irroratus s.l. and O. karoensis s.l.) associated closely with the boundaries of biomes (fynbos vs. grassland biomes) and geological formations (Cape Fold Belt vs. Great Escarpment).
- Full Text:
- Date Issued: 2020
- Authors: Taylor, Peter J , Kearney, Theresa , Dalton, Desire L , Chakona, Gamuchirai , Kelly, Christopher M R , Barker, Nigel P
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425481 , vital:72249 , xlink:href="https://doi.org/10.1093/zoolinnean/zlz134"
- Description: Mitochondrial DNA sequences (1137 bp) of the cytochrome b gene and craniodental and craniometric data were used to investigate the evolutionary relationships of six putative rodent taxa of Otomys (family Muridae: subfamily Murinae: tribe Otomyini) co-occurring in the Western Cape and Eastern Cape provinces of South Africa. Phylogenetic analysis of 20 new sequences together with craniodental and craniometric characters of 94 adult skulls reveal the existence of a unique lineage of Otomys cf. karoensis (named herein Otomys willani sp. nov.) from the Sneeuberg Centre of Floristic Endemism in the southern Drakensberg Mountain Range. Craniometric analysis distinguished O. karoensis from O. willani and identified a further four localities in the range of the latter species. We document southern range extensions of both Sloggett’s ice rat, Otomys sloggetti, and the vlei rat Otomys auratus to the Sneeuberg Mountain Range, in addition to appreciable genetic divergence between Sneeuberg and southern and central Drakensberg populations of O. sloggetti. Our results demonstrate parallel patterns of cryptic speciation in two co-occurring species complexes (Otomys irroratus s.l. and O. karoensis s.l.) associated closely with the boundaries of biomes (fynbos vs. grassland biomes) and geological formations (Cape Fold Belt vs. Great Escarpment).
- Full Text:
- Date Issued: 2020
Body mass and condition of a fynbos bird community investigating impacts of time, weather and raptor abundance from long-term citizen-science datasets
- Lee, Alan T K, Barnard, Phoebe, Fraser, Mike, Lennard, Chris, Smit, Ben, Oschadleus, Hans-Dieter
- Authors: Lee, Alan T K , Barnard, Phoebe , Fraser, Mike , Lennard, Chris , Smit, Ben , Oschadleus, Hans-Dieter
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441546 , vital:73897 , https://doi.org/10.2989/00306525.2019.1683093
- Description: Variation in body size, especially mass, is a function of local environmental conditions for any given species. Recent recorded decreases in body size of endotherms have been attributed to climate change in some cases. This prediction is based on the trend of smaller body size of endotherms in warmer climates (Bergmann’s rule) and it implies genetic responses rather than phenotypic flexibility. Alternatively, selection for smaller body size or lower mass could be explained by the starvation-predation hypothesis, where lighter individuals have a higher probability of escaping pursuing predators, such as raptors. Evidence that climate warming is driving patterns of size selection in birds in recent times has been mixed. We inspected data on 40 bird species contributed by bird ringers to the South African Ringing Scheme (SAFRING) for changes in body mass and condition as a function of time (year), minimum temperature of the day of capture, maximum temperature of the previous day, and rainfall data in the south-western Cape Floristic Region (fynbos) around Cape Town, South Africa, for the period 1988–2015. The region shows a warming trend over the study period (0.035 °C yr−1). Interannual body mass and condition change were poorly explained by year or temperature. High daily minimum temperature explained loss of body condition for four species, whereas evidence from recaptured birds indicated negative effects of increasing maximum daily temperature, as well as rain. For the alternative hypothesis, because raptor abundance is stable or only weakly declining, there is little evidence to suggest these as a driver influencing mass trends. Any decrease in body mass over the study period that we observed for birds appear more likely to be plastic responses to stress associated with temperature or rainfall at this time, rather than systematic selection for smaller body size, as predicted by Bergmann’s Rule.
- Full Text:
- Date Issued: 2020
- Authors: Lee, Alan T K , Barnard, Phoebe , Fraser, Mike , Lennard, Chris , Smit, Ben , Oschadleus, Hans-Dieter
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441546 , vital:73897 , https://doi.org/10.2989/00306525.2019.1683093
- Description: Variation in body size, especially mass, is a function of local environmental conditions for any given species. Recent recorded decreases in body size of endotherms have been attributed to climate change in some cases. This prediction is based on the trend of smaller body size of endotherms in warmer climates (Bergmann’s rule) and it implies genetic responses rather than phenotypic flexibility. Alternatively, selection for smaller body size or lower mass could be explained by the starvation-predation hypothesis, where lighter individuals have a higher probability of escaping pursuing predators, such as raptors. Evidence that climate warming is driving patterns of size selection in birds in recent times has been mixed. We inspected data on 40 bird species contributed by bird ringers to the South African Ringing Scheme (SAFRING) for changes in body mass and condition as a function of time (year), minimum temperature of the day of capture, maximum temperature of the previous day, and rainfall data in the south-western Cape Floristic Region (fynbos) around Cape Town, South Africa, for the period 1988–2015. The region shows a warming trend over the study period (0.035 °C yr−1). Interannual body mass and condition change were poorly explained by year or temperature. High daily minimum temperature explained loss of body condition for four species, whereas evidence from recaptured birds indicated negative effects of increasing maximum daily temperature, as well as rain. For the alternative hypothesis, because raptor abundance is stable or only weakly declining, there is little evidence to suggest these as a driver influencing mass trends. Any decrease in body mass over the study period that we observed for birds appear more likely to be plastic responses to stress associated with temperature or rainfall at this time, rather than systematic selection for smaller body size, as predicted by Bergmann’s Rule.
- Full Text:
- Date Issued: 2020
Building knowledge with theory: Unpacking complexity in doctoral writing
- Authors: Wilmot, Kirsten
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439480 , vital:73600 , https://www.ajol.info/index.php/cristal/article/view/203971
- Description: The use of theory to analyse and interpret empirical data is a valued practice in much social science doctoral research. A crucial aspect of this practice involves generating sophisticated theoretical understandings and critiques of phenomena in our social world. Despite the importance of theory, however, few concrete explanations of how to ‘theorise’exist in literature. This paper addresses this gap by demonstrating how a set of conceptual tools can be used to unpack what the craft of theorising looks like in explicit terms, and to reveal how this ability develops over time during the drafting process of dissertation writing. It does this by drawing on select texts from a successful doctoral dissertation, as well as an earlier draft version. In doing so, the paper provides an in-depth explanation of an essential process of doctoral research that is inherently known by many supervisors, yet seldom unpacked in explicit terms.
- Full Text:
- Date Issued: 2020
- Authors: Wilmot, Kirsten
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439480 , vital:73600 , https://www.ajol.info/index.php/cristal/article/view/203971
- Description: The use of theory to analyse and interpret empirical data is a valued practice in much social science doctoral research. A crucial aspect of this practice involves generating sophisticated theoretical understandings and critiques of phenomena in our social world. Despite the importance of theory, however, few concrete explanations of how to ‘theorise’exist in literature. This paper addresses this gap by demonstrating how a set of conceptual tools can be used to unpack what the craft of theorising looks like in explicit terms, and to reveal how this ability develops over time during the drafting process of dissertation writing. It does this by drawing on select texts from a successful doctoral dissertation, as well as an earlier draft version. In doing so, the paper provides an in-depth explanation of an essential process of doctoral research that is inherently known by many supervisors, yet seldom unpacked in explicit terms.
- Full Text:
- Date Issued: 2020
Characterisation of plasmodial transketolases and identification of potential inhibitors: an in silico study
- Boateng, Rita A, Tastan Bishop, Özlem, Musyoka, Thommas M
- Authors: Boateng, Rita A , Tastan Bishop, Özlem , Musyoka, Thommas M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429372 , vital:72605 , xlink:href="https://doi.org/10.1186/s12936-020-03512-1"
- Description: Plasmodial transketolase (PTKT) enzyme is one of the novel pharmacological targets being explored as potential anti-malarial drug target due to its functional role and low sequence identity to the human enzyme. Despite this, features contributing to such have not been exploited for anti-malarial drug design. Additionally, there are no anti-malarial drugs targeting PTKTs whereas the broad activity of these inhibitors against PTKTs from other Plasmodium spp. is yet to be reported. This study characterises different PTKTs [Plasmodium falciparum (PfTKT), Plasmodium vivax (PvTKT), Plasmodium ovale (PoTKT), Plasmodium malariae (PmTKT) and Plasmodium knowlesi (PkTKT) and the human homolog (HsTKT)] to identify key sequence and structural based differences as well as the identification of selective potential inhibitors against PTKTs.
- Full Text:
- Date Issued: 2020
- Authors: Boateng, Rita A , Tastan Bishop, Özlem , Musyoka, Thommas M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429372 , vital:72605 , xlink:href="https://doi.org/10.1186/s12936-020-03512-1"
- Description: Plasmodial transketolase (PTKT) enzyme is one of the novel pharmacological targets being explored as potential anti-malarial drug target due to its functional role and low sequence identity to the human enzyme. Despite this, features contributing to such have not been exploited for anti-malarial drug design. Additionally, there are no anti-malarial drugs targeting PTKTs whereas the broad activity of these inhibitors against PTKTs from other Plasmodium spp. is yet to be reported. This study characterises different PTKTs [Plasmodium falciparum (PfTKT), Plasmodium vivax (PvTKT), Plasmodium ovale (PoTKT), Plasmodium malariae (PmTKT) and Plasmodium knowlesi (PkTKT) and the human homolog (HsTKT)] to identify key sequence and structural based differences as well as the identification of selective potential inhibitors against PTKTs.
- Full Text:
- Date Issued: 2020
Chemical constituents, antioxidant and cytotoxicity properties of Leonotis leonurus used in the folklore management of neurological disorders in the Eastern Cape, South Africa
- Tonisi, Sipho, Okaiyeto, Kunle, Hoppe, Heinrich C, Mabinya, Leonard V, Nwodo, Uchechukwu U, Okoh, Anthony I
- Authors: Tonisi, Sipho , Okaiyeto, Kunle , Hoppe, Heinrich C , Mabinya, Leonard V , Nwodo, Uchechukwu U , Okoh, Anthony I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429384 , vital:72606 , xlink:href="https://doi.org/10.1007/s13205-020-2126-5"
- Description: In the present study, we evaluated the phytochemical compounds and antioxidant properties of chloroform, ethanol and acetone extracts for leaves and flowers of Leonutus leonurus (L. leonurus) alongside with their cytotoxic effects on human cervical carcinoma (HeLa) cell lines. The phytochemical compounds present in the leaves and flowers of L. leonurus included; phenolics, flavonoids and alkaloids. Their radicals scavenging effects against 2, 2-diphenyl-1-picrylhydrazyl [DPPH] 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonate) [ABTS·+], hydrogen peroxide, nitric oxide as well as metal chelating activities showed dose-dependent activities. Gas chromatography-mass spectrometry (GCMS) analyses revealed the presence of important bioactive compounds, which are associated with antioxidant; and the extracts exhibited toxicity effect against HeLa cells. The findings from this study divulge extracts of L. leonurus as prospective sources of antioxidant and anticancer agents; and hence, further study on their neuroprotective potentials becomes imperative.
- Full Text:
- Date Issued: 2020
- Authors: Tonisi, Sipho , Okaiyeto, Kunle , Hoppe, Heinrich C , Mabinya, Leonard V , Nwodo, Uchechukwu U , Okoh, Anthony I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429384 , vital:72606 , xlink:href="https://doi.org/10.1007/s13205-020-2126-5"
- Description: In the present study, we evaluated the phytochemical compounds and antioxidant properties of chloroform, ethanol and acetone extracts for leaves and flowers of Leonutus leonurus (L. leonurus) alongside with their cytotoxic effects on human cervical carcinoma (HeLa) cell lines. The phytochemical compounds present in the leaves and flowers of L. leonurus included; phenolics, flavonoids and alkaloids. Their radicals scavenging effects against 2, 2-diphenyl-1-picrylhydrazyl [DPPH] 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonate) [ABTS·+], hydrogen peroxide, nitric oxide as well as metal chelating activities showed dose-dependent activities. Gas chromatography-mass spectrometry (GCMS) analyses revealed the presence of important bioactive compounds, which are associated with antioxidant; and the extracts exhibited toxicity effect against HeLa cells. The findings from this study divulge extracts of L. leonurus as prospective sources of antioxidant and anticancer agents; and hence, further study on their neuroprotective potentials becomes imperative.
- Full Text:
- Date Issued: 2020
Climate responsive innovation within the agricultural curriculum and learning system
- Authors: van Staden, Wilma
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/389744 , vital:68479 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/186598"
- Description: The purpose of this paper is to outline the climate responsive innovation process within the agricultural innovation system of the North West Province, South Africa. The focus was on the embedded curriculum and learning activity system and its responses to social-ecological and earth system changes influenced by climate change. It outlines the barriers and processes hampering curriculum and learning innovations towards climate-smart responsiveness, and also examines the processes required to initiate micro and macro innovations. This paper focusses on how actors within the system can initiate curriculum innovation and climate responsiveness through micro innovations when supported and how this can lead to macro innovations. The system experienced various barriers during the innovation process and overcame many challenges during the journey towards climate-smart responsiveness through the identification of contradictions within the system, developing tools to assist in the transitioning process and expansion in the social-spatial dimension by establishing a learning network within the surrounding communities. The research indicated that the catalysing of the curriculum and learning system required specific tools, time and the understanding of the importance of micro-level innovation.
- Full Text:
- Date Issued: 2020
- Authors: van Staden, Wilma
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/389744 , vital:68479 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/186598"
- Description: The purpose of this paper is to outline the climate responsive innovation process within the agricultural innovation system of the North West Province, South Africa. The focus was on the embedded curriculum and learning activity system and its responses to social-ecological and earth system changes influenced by climate change. It outlines the barriers and processes hampering curriculum and learning innovations towards climate-smart responsiveness, and also examines the processes required to initiate micro and macro innovations. This paper focusses on how actors within the system can initiate curriculum innovation and climate responsiveness through micro innovations when supported and how this can lead to macro innovations. The system experienced various barriers during the innovation process and overcame many challenges during the journey towards climate-smart responsiveness through the identification of contradictions within the system, developing tools to assist in the transitioning process and expansion in the social-spatial dimension by establishing a learning network within the surrounding communities. The research indicated that the catalysing of the curriculum and learning system required specific tools, time and the understanding of the importance of micro-level innovation.
- Full Text:
- Date Issued: 2020
Clinically established biodegradable long acting injectables
- Nkanga, Christian I, Fisch, Andreas, Rad-Malkshahi, Mazda, Romic, Marieta D, Kittel, Birgit, Ullrich, Thomas, Wang, Jing, Krause, Rui W M, Adler, Sabine, Lammers, Twan, Hennink, Wim E, Ramazani, Farshad
- Authors: Nkanga, Christian I , Fisch, Andreas , Rad-Malkshahi, Mazda , Romic, Marieta D , Kittel, Birgit , Ullrich, Thomas , Wang, Jing , Krause, Rui W M , Adler, Sabine , Lammers, Twan , Hennink, Wim E , Ramazani, Farshad
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193386 , vital:45327 , xlink:href="https://doi.org/10.1016/j.addr.2020.11.008"
- Description: Long acting injectable formulations have been developed to sustain the action of drugs in the body over desired periods of time. These delivery platforms have been utilized for both systemic and local drug delivery applications. This review gives an overview of long acting injectable systems that are currently in clinical use. These products are categorized in three different groups: biodegradable polymeric systems, including microparticles and implants; micro and nanocrystal suspensions and oil-based formulations. Furthermore, the applications of these drug delivery platforms for the management of various chronic diseases are summarized. Finally, this review addresses industrial challenges regarding the development of long acting injectable formulations.
- Full Text:
- Date Issued: 2020
- Authors: Nkanga, Christian I , Fisch, Andreas , Rad-Malkshahi, Mazda , Romic, Marieta D , Kittel, Birgit , Ullrich, Thomas , Wang, Jing , Krause, Rui W M , Adler, Sabine , Lammers, Twan , Hennink, Wim E , Ramazani, Farshad
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193386 , vital:45327 , xlink:href="https://doi.org/10.1016/j.addr.2020.11.008"
- Description: Long acting injectable formulations have been developed to sustain the action of drugs in the body over desired periods of time. These delivery platforms have been utilized for both systemic and local drug delivery applications. This review gives an overview of long acting injectable systems that are currently in clinical use. These products are categorized in three different groups: biodegradable polymeric systems, including microparticles and implants; micro and nanocrystal suspensions and oil-based formulations. Furthermore, the applications of these drug delivery platforms for the management of various chronic diseases are summarized. Finally, this review addresses industrial challenges regarding the development of long acting injectable formulations.
- Full Text:
- Date Issued: 2020
Co-loading of isoniazid-grafted phthalocyanine-in-cyclodextrin and rifampicin in crude soybean lecithin liposomes: Formulation, spectroscopic and biological characterization
- Nkanga, Christian I, Roth, Michael, Walker, Roderick B, Noundou, Xavier S, Krause, Rui W M
- Authors: Nkanga, Christian I , Roth, Michael , Walker, Roderick B , Noundou, Xavier S , Krause, Rui W M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183481 , vital:43999 , xlink:href="https://doi.org/10.1166/jbn.2020.2880"
- Description: An inclusion complex of isoniazid-grafted phthalocyanine with gamma-cyclodextrin (Complex) was co-encapsulated with rifampicin (RIF) in crude soybean lecithin liposomes using a heating method. The encapsulation efficiency (%EE) of the Complex-RIF co-loaded liposomes (Rif-Complex-Lips) was determined using UV-Vis spectrophotometry. Rif-Complex-Lips formulations were evaluated using dynamic light scattering, transmission electron microscopy (TEM), 1H-NMR, absorption and emission spectroscopy. Dialysis was used for drug release study in two different media, pH 6.4 and 7.4. HeLa cells were used to assess potential cytotoxicity, and the uptake by lung fibroblasts and epithelial cells was investigated using fluorescence microscopy. The particle size and Zeta potential of Rif-Complex-Lips were approximately 594 nm and –50 mV. Spectroscopic analyses demonstrated molecular distribution of the cargo within the lipid core, and encapsulation efficiency of 58% for Complex and 86% for RIF. TEM analysis unveiled the existence of spherical nanoparticles in our samples, indicating the presence of liposomes. Rif-Complex-Lips exhibited much higher release rates for both INH and RIF at pH 6.4 compared to those tested at pH 7.4. In addition, there was no cytotoxicity on HeLa cells, but remarkable Rif-Complex-Lips internalization by peripheral lung fibroblasts and epithelial cells. Hence, Rif-Complex-Lips are promising vehicles for intracellular delivery of antimicrobial drugs.
- Full Text:
- Date Issued: 2020
- Authors: Nkanga, Christian I , Roth, Michael , Walker, Roderick B , Noundou, Xavier S , Krause, Rui W M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183481 , vital:43999 , xlink:href="https://doi.org/10.1166/jbn.2020.2880"
- Description: An inclusion complex of isoniazid-grafted phthalocyanine with gamma-cyclodextrin (Complex) was co-encapsulated with rifampicin (RIF) in crude soybean lecithin liposomes using a heating method. The encapsulation efficiency (%EE) of the Complex-RIF co-loaded liposomes (Rif-Complex-Lips) was determined using UV-Vis spectrophotometry. Rif-Complex-Lips formulations were evaluated using dynamic light scattering, transmission electron microscopy (TEM), 1H-NMR, absorption and emission spectroscopy. Dialysis was used for drug release study in two different media, pH 6.4 and 7.4. HeLa cells were used to assess potential cytotoxicity, and the uptake by lung fibroblasts and epithelial cells was investigated using fluorescence microscopy. The particle size and Zeta potential of Rif-Complex-Lips were approximately 594 nm and –50 mV. Spectroscopic analyses demonstrated molecular distribution of the cargo within the lipid core, and encapsulation efficiency of 58% for Complex and 86% for RIF. TEM analysis unveiled the existence of spherical nanoparticles in our samples, indicating the presence of liposomes. Rif-Complex-Lips exhibited much higher release rates for both INH and RIF at pH 6.4 compared to those tested at pH 7.4. In addition, there was no cytotoxicity on HeLa cells, but remarkable Rif-Complex-Lips internalization by peripheral lung fibroblasts and epithelial cells. Hence, Rif-Complex-Lips are promising vehicles for intracellular delivery of antimicrobial drugs.
- Full Text:
- Date Issued: 2020
Combination of CTec2 and GH5 or GH26 Endo-Mannanases for Effective Lignocellulosic Biomass Degradation
- Malgas, Samkelo, Pletschke, Brett I
- Authors: Malgas, Samkelo , Pletschke, Brett I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429397 , vital:72607 , xlink:href="https://doi.org/10.3390/catal10101193"
- Description: Among endo-mannanases, glycoside hydrolase (GH) family 26 enzymes have been shown to be more catalytically active than GH5 enzymes on mannans. However, only GH5 endo-mannanases have been used for the formulation of enzyme cocktails. In this study, Bacillus sp.-derived GH5 and GH26 endo-mannanases were comparatively analysed biochemically for their synergistic action with a commercial cellulase blend, CTec2, during pre-treated lignocellulose degradation. Substrate specificity and thermo-stability studies on mannan substrates showed that GH26 endo-mannanase was more catalytically active and stable than GH5. GH26 also exhibited higher binding affinity for mannan than GH5, while GH5 showed more affinity for lignocellulosic substrates than GH26. Applying the endo-mannanases in combination with CTec2 for lignocellulose degradation led to synergism with a 1.3-fold increase in reducing sugar release compared to when CTec2 was used alone. This study showed that using the activity of endo-mannanases displayed with model substrates is a poor predictor of their activity and synergism on complex lignocelluloses.
- Full Text:
- Date Issued: 2020
- Authors: Malgas, Samkelo , Pletschke, Brett I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429397 , vital:72607 , xlink:href="https://doi.org/10.3390/catal10101193"
- Description: Among endo-mannanases, glycoside hydrolase (GH) family 26 enzymes have been shown to be more catalytically active than GH5 enzymes on mannans. However, only GH5 endo-mannanases have been used for the formulation of enzyme cocktails. In this study, Bacillus sp.-derived GH5 and GH26 endo-mannanases were comparatively analysed biochemically for their synergistic action with a commercial cellulase blend, CTec2, during pre-treated lignocellulose degradation. Substrate specificity and thermo-stability studies on mannan substrates showed that GH26 endo-mannanase was more catalytically active and stable than GH5. GH26 also exhibited higher binding affinity for mannan than GH5, while GH5 showed more affinity for lignocellulosic substrates than GH26. Applying the endo-mannanases in combination with CTec2 for lignocellulose degradation led to synergism with a 1.3-fold increase in reducing sugar release compared to when CTec2 was used alone. This study showed that using the activity of endo-mannanases displayed with model substrates is a poor predictor of their activity and synergism on complex lignocelluloses.
- Full Text:
- Date Issued: 2020
Conserved bacterial genomes from two geographically isolated peritidal stromatolite formations shed light on potential functional guilds
- Waterworth, Samantha C, Isemonger, Eric W, Rees, Evan R, Dorrington, Rosemary A
- Authors: Waterworth, Samantha C , Isemonger, Eric W , Rees, Evan R , Dorrington, Rosemary A
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429411 , vital:72608 , xlink:href="https://doi.org/10.1111/1758-2229.12916"
- Description: Stromatolites are complex microbial mats that form lithified layers. Fossilized stromatolites are the oldest evidence of cellular life on Earth, dating back over3.4 billion years. Modern stromatolites are relatively rare but may provide clues about the function and evolution of their ancient counterparts. In this study, we focus on peritidal stromatolites occurring at Cape Recife and Schoenmakerskop on the southeastern South African coastline, the former being morphologically and structurally similar to fossilized phosphatic stromatolites formations. Using assembled shotgun metagenomic analysis, we obtained 183 genomic bins, of which the most dominant taxa were from the Cyanobacteria phylum. We identified functional gene sets in genomic bins conserved across two geographically isolated stromatolite formations, which included relatively high copy numbers of genes involved in the reduction of nitrates and phosphatic compounds. Additionally, we found little evidence of Archaeal species in these stromatolites, suggesting that they may not play an important role in peritidal stromatolite formations, as proposed for hypersaline formations.
- Full Text:
- Date Issued: 2020
- Authors: Waterworth, Samantha C , Isemonger, Eric W , Rees, Evan R , Dorrington, Rosemary A
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429411 , vital:72608 , xlink:href="https://doi.org/10.1111/1758-2229.12916"
- Description: Stromatolites are complex microbial mats that form lithified layers. Fossilized stromatolites are the oldest evidence of cellular life on Earth, dating back over3.4 billion years. Modern stromatolites are relatively rare but may provide clues about the function and evolution of their ancient counterparts. In this study, we focus on peritidal stromatolites occurring at Cape Recife and Schoenmakerskop on the southeastern South African coastline, the former being morphologically and structurally similar to fossilized phosphatic stromatolites formations. Using assembled shotgun metagenomic analysis, we obtained 183 genomic bins, of which the most dominant taxa were from the Cyanobacteria phylum. We identified functional gene sets in genomic bins conserved across two geographically isolated stromatolite formations, which included relatively high copy numbers of genes involved in the reduction of nitrates and phosphatic compounds. Additionally, we found little evidence of Archaeal species in these stromatolites, suggesting that they may not play an important role in peritidal stromatolite formations, as proposed for hypersaline formations.
- Full Text:
- Date Issued: 2020
Contradictions in womxn’s experiences of pre-abortion counselling in South Africa: Implications for client‐centred practice
- Mavuso, Jabulile M-J J, Macleod, Catriona I
- Authors: Mavuso, Jabulile M-J J , Macleod, Catriona I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443638 , vital:74140 , xlink:href="https://doi.org/10.1111/nin.12330"
- Description: Pre-abortion counselling may play a key role in abortion seekers’ understanding of their decision to terminate a pregnancy and the subsequent emotions that they feel. In this paper, we report on a study conducted in the Eastern Cape province of South Africa concerning womxn's experiences of the pre-abortion counselling offered as part of the implementation of the Choice of Termination Act that governs the provision of legal abortion in the country. Using a narrative-discursive lens, the analysis revealed four micro-narratives in which participants appreciated non-directive and empathic counselling, as well as being provided with information. They also indicated that the counselling was upsetting and hurtful, particularly when providers drew on the awfulisation of abortion discourse to suggest that abortion leads to terrible consequences, and foetal personhood discourse to intimate that terminating the pregnancy is wrong and other alternatives (adoption, parenting) are better. The connection between these broadly positive and negative responses may lie in the dominance of anti-abortion discourses coupled with the powerful positioning of healthcare providers as experts. The attendant disempowerment of clients within the health clinic setting may constrain pregnant people's ability to question such ‘expert’ information. The implications for feminist client-centred pre-abortion counselling are discussed.
- Full Text:
- Date Issued: 2020
- Authors: Mavuso, Jabulile M-J J , Macleod, Catriona I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443638 , vital:74140 , xlink:href="https://doi.org/10.1111/nin.12330"
- Description: Pre-abortion counselling may play a key role in abortion seekers’ understanding of their decision to terminate a pregnancy and the subsequent emotions that they feel. In this paper, we report on a study conducted in the Eastern Cape province of South Africa concerning womxn's experiences of the pre-abortion counselling offered as part of the implementation of the Choice of Termination Act that governs the provision of legal abortion in the country. Using a narrative-discursive lens, the analysis revealed four micro-narratives in which participants appreciated non-directive and empathic counselling, as well as being provided with information. They also indicated that the counselling was upsetting and hurtful, particularly when providers drew on the awfulisation of abortion discourse to suggest that abortion leads to terrible consequences, and foetal personhood discourse to intimate that terminating the pregnancy is wrong and other alternatives (adoption, parenting) are better. The connection between these broadly positive and negative responses may lie in the dominance of anti-abortion discourses coupled with the powerful positioning of healthcare providers as experts. The attendant disempowerment of clients within the health clinic setting may constrain pregnant people's ability to question such ‘expert’ information. The implications for feminist client-centred pre-abortion counselling are discussed.
- Full Text:
- Date Issued: 2020
Contradictions in womxn’s experiences of pre-abortion counselling in South Africa: Implications for client‐centred practice
- Mavuso, Jabulile M-J J, Macleod, Catriona I
- Authors: Mavuso, Jabulile M-J J , Macleod, Catriona I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444291 , vital:74214 , xlink:href="https://doi.org/10.1111/nin.12330"
- Description: Pre-abortion counselling may play a key role in abortion seekers’ understanding of their decision to terminate a pregnancy and the subsequent emotions that they feel. In this paper, we report on a study conducted in the Eastern Cape province of South Africa concerning womxn's experiences of the pre-abortion counselling offered as part of the implementation of the Choice of Termination Act that governs the provision of legal abortion in the country. Using a narrative-discursive lens, the analysis revealed four micro-narratives in which participants appreciated non-directive and empathic counselling, as well as being provided with information. They also indicated that the counselling was upsetting and hurtful, particularly when providers drew on the awfulisation of abortion discourse to suggest that abortion leads to terrible consequences, and foetal personhood discourse to intimate that terminating the pregnancy is wrong and other alternatives (adoption, parenting) are better. The connection between these broadly positive and negative responses may lie in the dominance of anti-abortion discourses coupled with the powerful positioning of healthcare providers as experts. The attendant disempowerment of clients within the health clinic setting may constrain pregnant people's ability to question such ‘expert’ information. The implications for feminist client-centred pre-abortion counselling are discussed.
- Full Text:
- Date Issued: 2020
- Authors: Mavuso, Jabulile M-J J , Macleod, Catriona I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444291 , vital:74214 , xlink:href="https://doi.org/10.1111/nin.12330"
- Description: Pre-abortion counselling may play a key role in abortion seekers’ understanding of their decision to terminate a pregnancy and the subsequent emotions that they feel. In this paper, we report on a study conducted in the Eastern Cape province of South Africa concerning womxn's experiences of the pre-abortion counselling offered as part of the implementation of the Choice of Termination Act that governs the provision of legal abortion in the country. Using a narrative-discursive lens, the analysis revealed four micro-narratives in which participants appreciated non-directive and empathic counselling, as well as being provided with information. They also indicated that the counselling was upsetting and hurtful, particularly when providers drew on the awfulisation of abortion discourse to suggest that abortion leads to terrible consequences, and foetal personhood discourse to intimate that terminating the pregnancy is wrong and other alternatives (adoption, parenting) are better. The connection between these broadly positive and negative responses may lie in the dominance of anti-abortion discourses coupled with the powerful positioning of healthcare providers as experts. The attendant disempowerment of clients within the health clinic setting may constrain pregnant people's ability to question such ‘expert’ information. The implications for feminist client-centred pre-abortion counselling are discussed.
- Full Text:
- Date Issued: 2020
CSR, Corporate Heritage Identity and Social Learning
- Ijabadeniyi, Abosede, Lotz-Sisitka, Heila
- Authors: Ijabadeniyi, Abosede , Lotz-Sisitka, Heila
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436841 , vital:73309 , ISBN 978-981-15-6370-6 , https://doi.org/10.1007/978-981-15-6370-6_8
- Description: Prevailing approaches to the structural challenges of Corporate Social Responsibility (CSR) tend to be monolithic and skewed towards CSR at the organisational level. Albeit, mirroring CSR at the organisational level with activities of practitioners at the social level can offer new reflexive approaches for identifying capabilities for and understanding thresholds of social learning. This chapter maps out how identity perspectives to CSR can offer new approaches for surfacing emergent properties inherent in the uptake of CSR institutionally and in practice. The chapter also presents an overview of the interplay be-tween structure and agency (prescribed and actual CSR practices) and its underlying in-strumental role for illuminating systemic factors which perpetuate such capabilities and thresholds. Using a morphogenetic theo-ry of change, the chapter offers a framework for approaching CSR-based corporate identity. Empirical evidence from the applied framework is thereafter presented, in the context of the agro-processing industry based on a content analysis of an-nual reports, in-depth-interview data generated from four sus-tainability managers and corporate communication officers and the practices of extension and Local Economic Development (LED) officers. The framework demonstrates that companies with a disintegrated CSR identity inherently have more capaci-ty to be change agents. Similarly, a strong corporate heritage identity is not indicative of a reciprocal link between espoused values and activity. Conversely, an enduring corporate herit-age identity may not necessarily be improvisatory for social learning. In conclusion, the chapter gives an overview of a tax-onomy of agential capabilities and associated cognitive re-sources inherent in the interaction between structural-cultural and personal emergent properties, which can initiate the posi-tioning of social learning at the forefront of organisational de-liberations.
- Full Text:
- Date Issued: 2020
- Authors: Ijabadeniyi, Abosede , Lotz-Sisitka, Heila
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436841 , vital:73309 , ISBN 978-981-15-6370-6 , https://doi.org/10.1007/978-981-15-6370-6_8
- Description: Prevailing approaches to the structural challenges of Corporate Social Responsibility (CSR) tend to be monolithic and skewed towards CSR at the organisational level. Albeit, mirroring CSR at the organisational level with activities of practitioners at the social level can offer new reflexive approaches for identifying capabilities for and understanding thresholds of social learning. This chapter maps out how identity perspectives to CSR can offer new approaches for surfacing emergent properties inherent in the uptake of CSR institutionally and in practice. The chapter also presents an overview of the interplay be-tween structure and agency (prescribed and actual CSR practices) and its underlying in-strumental role for illuminating systemic factors which perpetuate such capabilities and thresholds. Using a morphogenetic theo-ry of change, the chapter offers a framework for approaching CSR-based corporate identity. Empirical evidence from the applied framework is thereafter presented, in the context of the agro-processing industry based on a content analysis of an-nual reports, in-depth-interview data generated from four sus-tainability managers and corporate communication officers and the practices of extension and Local Economic Development (LED) officers. The framework demonstrates that companies with a disintegrated CSR identity inherently have more capaci-ty to be change agents. Similarly, a strong corporate heritage identity is not indicative of a reciprocal link between espoused values and activity. Conversely, an enduring corporate herit-age identity may not necessarily be improvisatory for social learning. In conclusion, the chapter gives an overview of a tax-onomy of agential capabilities and associated cognitive re-sources inherent in the interaction between structural-cultural and personal emergent properties, which can initiate the posi-tioning of social learning at the forefront of organisational de-liberations.
- Full Text:
- Date Issued: 2020
Curriculating powerful knowledge for public managers and administrators
- McKenna, Sioux, Harran, Marcelle, Lück, Jacqueline
- Authors: McKenna, Sioux , Harran, Marcelle , Lück, Jacqueline
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187160 , vital:44575 , xlink:href="https://doi.org/10.1080/18146627.2019.1652103"
- Description: Public Management and Public Administration are important professions for an emerging democracy such as South Africa. They operate as the interface between state and public and are responsible for enacting many of the government's policies and social initiatives. Concerns about a lack of capacity in the sector suggest that those in these roles may be unable to meet the demands of the workplace. This article reports on a study that responded to calls for the curriculum to address such concerns by interrogating the knowledge structures of Public Management and Public Administration programmes in higher education. Interviews, textbooks and course guides were analysed to illuminate the forms of knowledge being legitimated in curricula. The study found that the focus on knowledge, skills and processes might be at the expense of a focus on the development of particular attributes or dispositions in the knowers. Furthermore, the knowledge level focus was limited in that it was highly contextualised and “light” on theory, raising questions about the acquisition of powerful knowledge needed for good governance and critical engagement in the public sector. The study recommends that both programmes include more conceptual knowledge; exposure to critical powerful forms of knowledge; and the development of particular attributes and dispositions.
- Full Text:
- Date Issued: 2020
- Authors: McKenna, Sioux , Harran, Marcelle , Lück, Jacqueline
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187160 , vital:44575 , xlink:href="https://doi.org/10.1080/18146627.2019.1652103"
- Description: Public Management and Public Administration are important professions for an emerging democracy such as South Africa. They operate as the interface between state and public and are responsible for enacting many of the government's policies and social initiatives. Concerns about a lack of capacity in the sector suggest that those in these roles may be unable to meet the demands of the workplace. This article reports on a study that responded to calls for the curriculum to address such concerns by interrogating the knowledge structures of Public Management and Public Administration programmes in higher education. Interviews, textbooks and course guides were analysed to illuminate the forms of knowledge being legitimated in curricula. The study found that the focus on knowledge, skills and processes might be at the expense of a focus on the development of particular attributes or dispositions in the knowers. Furthermore, the knowledge level focus was limited in that it was highly contextualised and “light” on theory, raising questions about the acquisition of powerful knowledge needed for good governance and critical engagement in the public sector. The study recommends that both programmes include more conceptual knowledge; exposure to critical powerful forms of knowledge; and the development of particular attributes and dispositions.
- Full Text:
- Date Issued: 2020
Decorated titania fibers as photocatalysts for hydrogen generation and organic matter degradation
- Mapukata, Sivuyisiwe, Hainer, Andrew S, Lanterna, Anabel E, Scaiano, Juan C, Nyokong, Tebello
- Authors: Mapukata, Sivuyisiwe , Hainer, Andrew S , Lanterna, Anabel E , Scaiano, Juan C , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186573 , vital:44513 , xlink:href="https://doi.org/10.1016/j.jphotochem.2019.112185"
- Description: Heterogenous photocatalysts based on electrospun fibers composed of polyvinylpyrrolidone and titanium propoxide were prepared and heated at 500, 750 and 950 °C to obtain anatase and rutile fibers. The fibers were then decorated with Pd and Co nanoparticles as well as a symmetrical zinc phthalocyanine (Pc). The fibrous materials obtained have a paper-like macroscopic appearance allowing for easy handling and separation. The photocatalytic activities of the new materials were evaluated for the generation of H2 upon UV (368 nm) or visible (630 nm) light excitation. Depending on the heat treatment or the post-synthetic decoration method, the materials show higher, or similar, activity compared to P25-TiO2, with superior ease of separation. The catalysts showed ability to degrade organic matter, with MeOH used as a model compound. This is of considerable importance for potential water treatment applications that will require flow-compatible materials.
- Full Text:
- Date Issued: 2020
- Authors: Mapukata, Sivuyisiwe , Hainer, Andrew S , Lanterna, Anabel E , Scaiano, Juan C , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186573 , vital:44513 , xlink:href="https://doi.org/10.1016/j.jphotochem.2019.112185"
- Description: Heterogenous photocatalysts based on electrospun fibers composed of polyvinylpyrrolidone and titanium propoxide were prepared and heated at 500, 750 and 950 °C to obtain anatase and rutile fibers. The fibers were then decorated with Pd and Co nanoparticles as well as a symmetrical zinc phthalocyanine (Pc). The fibrous materials obtained have a paper-like macroscopic appearance allowing for easy handling and separation. The photocatalytic activities of the new materials were evaluated for the generation of H2 upon UV (368 nm) or visible (630 nm) light excitation. Depending on the heat treatment or the post-synthetic decoration method, the materials show higher, or similar, activity compared to P25-TiO2, with superior ease of separation. The catalysts showed ability to degrade organic matter, with MeOH used as a model compound. This is of considerable importance for potential water treatment applications that will require flow-compatible materials.
- Full Text:
- Date Issued: 2020
Delineating functional properties of a cello-oligosaccharide and Bglucan specific cellobiohydrolase (GH5_38): Its synergism with Cel6A and Cel7A for B-(1,3)-(1,4)-glucan degradation
- Mafa, Mpho S, Malgas, Samkelo, Rashamuse, Konanani, Pletschke, Brett I
- Authors: Mafa, Mpho S , Malgas, Samkelo , Rashamuse, Konanani , Pletschke, Brett I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429425 , vital:72609 , xlink:href="https://doi.org/10.1016/j.carres.2020.108081"
- Description: Cellulase cocktails formulated to degrade crystalline cellulose generally contain cellobiohydrolases (CBHs), referred to as CBHI (Cel7A) and CBHII (Cel6A), as the major constituents. The combined hydrolytic activities of CBHI and CBHII improve the release of fermentable sugars (β-1,4-cellobiose as the main product) from crystalline cellulose. In this study, a novel cellobiohydrolase (Exg-D) sourced from a metagenome of hindgut bacterial symbionts of a termite was heterologouly expressed, purified, and functionally characterised. Exg-D specific activity was higher on insoluble barley β-glucan (38.94 U/mg protein), soluble wheat flour β-glucan (12.71 U/mg protein) and oat β-glucan (8.89 U/mg protein) compared to cellulosic substrates; Avicel and CMC. We further explored Exg-D activity on the unpretreated or NaOH-pretreated (mercerised) Avicel and compared its activity to commercially available CBHI and CBHII on these celluloses. CBHI displayed the highest activity of 4.74 U/mg protein on mercerised cellulose followed by CBHII (2.14 U/mg protein), while Exg-D activity on untreated and mercerised cellulose was 1.66 and 1.67 U/mg protein, respectively. The high activity of CBHI was supported by binding assays, which revealed that CBHI has a higher binding capacity towards crystalline cellulose compared to Exg-D and CBHII. Only CBHI and CBHII showed synergism during the hydrolysis of mercerised Avicel, showing a degree of synergy (DS) of about 1.299 and yielded about 1.43 μmol/ml of reducing sugars higher than control. In contrast, Exg-D and CBHII displayed synergism during β-glucan degradation, displaying a DS of about 1.22. Thus, we propose that Exg-D should only be used synergistically with other CBHs to degrade mixed linked-β-(1,3)-(1,4)-glucan.
- Full Text:
- Date Issued: 2020
- Authors: Mafa, Mpho S , Malgas, Samkelo , Rashamuse, Konanani , Pletschke, Brett I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429425 , vital:72609 , xlink:href="https://doi.org/10.1016/j.carres.2020.108081"
- Description: Cellulase cocktails formulated to degrade crystalline cellulose generally contain cellobiohydrolases (CBHs), referred to as CBHI (Cel7A) and CBHII (Cel6A), as the major constituents. The combined hydrolytic activities of CBHI and CBHII improve the release of fermentable sugars (β-1,4-cellobiose as the main product) from crystalline cellulose. In this study, a novel cellobiohydrolase (Exg-D) sourced from a metagenome of hindgut bacterial symbionts of a termite was heterologouly expressed, purified, and functionally characterised. Exg-D specific activity was higher on insoluble barley β-glucan (38.94 U/mg protein), soluble wheat flour β-glucan (12.71 U/mg protein) and oat β-glucan (8.89 U/mg protein) compared to cellulosic substrates; Avicel and CMC. We further explored Exg-D activity on the unpretreated or NaOH-pretreated (mercerised) Avicel and compared its activity to commercially available CBHI and CBHII on these celluloses. CBHI displayed the highest activity of 4.74 U/mg protein on mercerised cellulose followed by CBHII (2.14 U/mg protein), while Exg-D activity on untreated and mercerised cellulose was 1.66 and 1.67 U/mg protein, respectively. The high activity of CBHI was supported by binding assays, which revealed that CBHI has a higher binding capacity towards crystalline cellulose compared to Exg-D and CBHII. Only CBHI and CBHII showed synergism during the hydrolysis of mercerised Avicel, showing a degree of synergy (DS) of about 1.299 and yielded about 1.43 μmol/ml of reducing sugars higher than control. In contrast, Exg-D and CBHII displayed synergism during β-glucan degradation, displaying a DS of about 1.22. Thus, we propose that Exg-D should only be used synergistically with other CBHs to degrade mixed linked-β-(1,3)-(1,4)-glucan.
- Full Text:
- Date Issued: 2020
Design, Optimization, Manufacture and Characterization of Efavirenz-Loaded Flaxseed Oil Nanoemulsions
- Mazonde, Priveledge, Khamanga, Sandile M, Walker, Roderick B
- Authors: Mazonde, Priveledge , Khamanga, Sandile M , Walker, Roderick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183183 , vital:43919 , xlink:href="https://doi.org/10.3390/pharmaceutics12090797"
- Description: The formation, manufacture and characterization of low energy water-in-oil (w/o) nanoemulsions prepared using cold pressed flaxseed oil containing efavirenz was investigated. Pseudo-ternary phase diagrams were constructed to identify the nanoemulsion region(s). Other potential lipid-based drug delivery phases containing flaxseed oil with 1:1 m/m surfactant mixture of Tween® 80, Span® 20 and different amounts of ethanol were tested to characterize the impact of surfactant mixture on emulsion formation. Flaxseed oil was used as the oil phase as efavirenz exhibited high solubility in the vehicle when compared to other vegetable oils tested. Optimization of surfactant mixtures was undertaken using design of experiments, specifically a D-optimal design with the flaxseed oil content set at 10% m/m. Two solutions from the desired optimization function were produced based on desirability and five nanoemulsion formulations were produced and characterized in terms of in vitro release of efavirenz, physical and chemical stability. Metastable nanoemulsions containing 10% m/m flaxseed oil were successfully manufactured and significant isotropic gel (semisolid) and o/w emulsions were observed during phase behavior studies. Droplet sizes ranged between 156 and 225 nm, zeta potential between −24 and −41 mV and all formulations were found to be monodisperse with polydispersity indices ≤ 0.487.
- Full Text:
- Date Issued: 2020
- Authors: Mazonde, Priveledge , Khamanga, Sandile M , Walker, Roderick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183183 , vital:43919 , xlink:href="https://doi.org/10.3390/pharmaceutics12090797"
- Description: The formation, manufacture and characterization of low energy water-in-oil (w/o) nanoemulsions prepared using cold pressed flaxseed oil containing efavirenz was investigated. Pseudo-ternary phase diagrams were constructed to identify the nanoemulsion region(s). Other potential lipid-based drug delivery phases containing flaxseed oil with 1:1 m/m surfactant mixture of Tween® 80, Span® 20 and different amounts of ethanol were tested to characterize the impact of surfactant mixture on emulsion formation. Flaxseed oil was used as the oil phase as efavirenz exhibited high solubility in the vehicle when compared to other vegetable oils tested. Optimization of surfactant mixtures was undertaken using design of experiments, specifically a D-optimal design with the flaxseed oil content set at 10% m/m. Two solutions from the desired optimization function were produced based on desirability and five nanoemulsion formulations were produced and characterized in terms of in vitro release of efavirenz, physical and chemical stability. Metastable nanoemulsions containing 10% m/m flaxseed oil were successfully manufactured and significant isotropic gel (semisolid) and o/w emulsions were observed during phase behavior studies. Droplet sizes ranged between 156 and 225 nm, zeta potential between −24 and −41 mV and all formulations were found to be monodisperse with polydispersity indices ≤ 0.487.
- Full Text:
- Date Issued: 2020