Coastal fishes of the western Indian Ocean
- Heemstra, Phillip C. 1941-, Heemstra, Elaine, Ebert, Dave, Holleman, Wouter, Randall, John E
- Authors: Heemstra, Phillip C. 1941- , Heemstra, Elaine , Ebert, Dave , Holleman, Wouter , Randall, John E
- Date: 2022
- Subjects: Marine fishes Indian Ocean , Marine fishes Indian Ocean Identification
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/310495 , vital:59157 , ISBN 978-1-990951-23-7 , ISBN 978-1-998950-35-5 , ISBN 978-1-990951-28-2
- Description: The primary purpose of this book is to provide a means of identifying the more than 3 200 species of coastal fishes known to occur in the Western Indian Ocean (WIO). Coastal fishes are those that inhabit waters generally less than ~200 m deep, the waters over continental and insular shelves, and upper continental slopes. The book also includes some oceanic species and species that live in deeper water, but are sometimes caught in trawls in less than 200 m, or that migrate into shallower waters at night to feed. The Western Indian Ocean (WIO), as treated in these volumes, is the area between Cape Point, South Africa, and 77°34' E, at Kanyakumari (formerly Cape Cormorin), the southernmost point of India, and to 40° S, just south of St Paul Island. Although considered as separate water bodies, the Red Sea and Persian/Arabian Gulf have been included. Some contributors have also chosen to include species from Sri Lanka. The region thus encompasses the entire east and southern coasts of Africa, Madagascar and the various island clusters of the Comoros, the Seychelles, the Maldive and Lakshadweep islands, the Chagos Archipelago and the islands and sea mounts of the Mascarene Plateau, to as far as 40° S, and thus some fishes from St Paul and Amsterdam Islands have been included. This large expanse, stretching from tropical waters of the northwestern Indian Ocean to the warm temperate waters of False Bay, South Africa, includes a number of poorly known biogeographic areas. A map of the entire Indian Ocean is placed on the inside front cover of each printed volume, with some areas in greater detail on the inside back cover. The book does not include distribution maps for species, but gives localities from which species are known, with emphasis on WIO localities; our understanding of distributions of many species is often incomplete. Fishes are the most abundant and diverse group of vertebrates and have colonised every aquatic habitat on Earth: the oceans, lakes, rivers and caves, from polar seas at –2 °C to hot, freshwater springs at 44 °C, and from tropical reefs and mangrove forests to the deepest ocean depths. Fishes are also the most poorly known group of vertebrates. In the 2006 edition of Joseph Nelson’s Fishes of the World the estimate of the number of species of extant fishes worldwide stood at about 23 000. This number is growing annually, and was thought to be about 33 460 species at the end of 2016 (www.fishwisepro.com). Between the years 2000 and 2015 an average of 150 new species of marine fishes were described each year – of which 10% of the total (156 species) were from the WIO. The WIO is home to about 15% of all the marine fish species in the world’s oceans. Another measure of the diversity of fishes of this area is its relatively high level of endemicity, particularly around southern Africa and in the Red Sea. About 13% of southern African marine fishes are endemic, most of these in only five families: Clinidae with about 44 endemic species, Gobiidae with 28, Sparidae with 28, Pentanchidae with 6, and Batrachoididae with 7 endemic species. In the Red Sea at least 170 of the more than 1100 species are endemic. The WIO region is also home to a large human population, representing a wide range of ethnic and cultural backgrounds. The area includes the countries of South Africa, Mozambique, Tanzania, Kenya, Somalia, Eritrea, Sudan, Egypt, Israel, Jordan, Saudi Arabia, Yemen, Oman, United Arab Emirates, Qatar, Bahrain, Kuwait, Iraq, Iran, Pakistan, India and Sri Lanka, as well as the many island nations and territories. Many of the people living in coastal areas are dependent on fish catches and other marine resources for both sustenance and often a livelihood, as highly diversified artisanal fisheries make up the bulk of the fishing effort in the region. And, as elsewhere in the world, many of the fish resources have been compromised by commercial interests (including those of other countries), often leaving fish stocks in a poor state. This book has a number of purposes, all of which coalesce around providing users with a better understanding of the area’s fishes and their environment. Accordingly, it includes a number of background chapters covering subjects as diverse as the oceanography of the region, and the history and evolution of the bony fishes. In recent years genetic analysis has proved to be a powerful tool for taxonomists. In many instances molecular results have caused taxonomists to rethink both the definitions of certain taxa and the interrelationships of taxa. In some instances, what were long considered cohesive (monophyletic) taxa were found to include groups of fishes that are in fact not closely related (paraphyletic), while in other instances taxa thought to be distinct were found not to be, meriting their merging with other existing taxa. At times, long-accepted family groups have been divided into two or more distinct families, or separate families have been combined into a single one. Where possible such changes in our understanding of the relationships of fishes are reflected in these volumes. Where some contributors have taken a more conservative approach by awaiting more research and not adopting these changes, alternative taxonomies are noted (see also the introductory chapter on Naming organisms and determining their relationships). For each species in the book, the literature pertinent to that species in the WIO is given: the original species description reference, synonyms for the region and other important taxonomic and biological references. For many commercially important species or fishes of interest to anglers there is additional information on life history, size and capture, and for some but not all species, their IUCN conservation status if Near Threatened, Vulnerable, Endangered or Critically Endangered (in the first instance, valid at the time of writing. See www.iucnredlist.org for current information. Note: we have not included the IUCN conservation status where species are of Least Concern or Data Deficient). Most species are illustrated with photographs, drawings or paintings. Colour photographs and paintings are provided on plates for each volume. , 1st Edition
- Full Text:
- Date Issued: 2022
- Authors: Heemstra, Phillip C. 1941- , Heemstra, Elaine , Ebert, Dave , Holleman, Wouter , Randall, John E
- Date: 2022
- Subjects: Marine fishes Indian Ocean , Marine fishes Indian Ocean Identification
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/310495 , vital:59157 , ISBN 978-1-990951-23-7 , ISBN 978-1-998950-35-5 , ISBN 978-1-990951-28-2
- Description: The primary purpose of this book is to provide a means of identifying the more than 3 200 species of coastal fishes known to occur in the Western Indian Ocean (WIO). Coastal fishes are those that inhabit waters generally less than ~200 m deep, the waters over continental and insular shelves, and upper continental slopes. The book also includes some oceanic species and species that live in deeper water, but are sometimes caught in trawls in less than 200 m, or that migrate into shallower waters at night to feed. The Western Indian Ocean (WIO), as treated in these volumes, is the area between Cape Point, South Africa, and 77°34' E, at Kanyakumari (formerly Cape Cormorin), the southernmost point of India, and to 40° S, just south of St Paul Island. Although considered as separate water bodies, the Red Sea and Persian/Arabian Gulf have been included. Some contributors have also chosen to include species from Sri Lanka. The region thus encompasses the entire east and southern coasts of Africa, Madagascar and the various island clusters of the Comoros, the Seychelles, the Maldive and Lakshadweep islands, the Chagos Archipelago and the islands and sea mounts of the Mascarene Plateau, to as far as 40° S, and thus some fishes from St Paul and Amsterdam Islands have been included. This large expanse, stretching from tropical waters of the northwestern Indian Ocean to the warm temperate waters of False Bay, South Africa, includes a number of poorly known biogeographic areas. A map of the entire Indian Ocean is placed on the inside front cover of each printed volume, with some areas in greater detail on the inside back cover. The book does not include distribution maps for species, but gives localities from which species are known, with emphasis on WIO localities; our understanding of distributions of many species is often incomplete. Fishes are the most abundant and diverse group of vertebrates and have colonised every aquatic habitat on Earth: the oceans, lakes, rivers and caves, from polar seas at –2 °C to hot, freshwater springs at 44 °C, and from tropical reefs and mangrove forests to the deepest ocean depths. Fishes are also the most poorly known group of vertebrates. In the 2006 edition of Joseph Nelson’s Fishes of the World the estimate of the number of species of extant fishes worldwide stood at about 23 000. This number is growing annually, and was thought to be about 33 460 species at the end of 2016 (www.fishwisepro.com). Between the years 2000 and 2015 an average of 150 new species of marine fishes were described each year – of which 10% of the total (156 species) were from the WIO. The WIO is home to about 15% of all the marine fish species in the world’s oceans. Another measure of the diversity of fishes of this area is its relatively high level of endemicity, particularly around southern Africa and in the Red Sea. About 13% of southern African marine fishes are endemic, most of these in only five families: Clinidae with about 44 endemic species, Gobiidae with 28, Sparidae with 28, Pentanchidae with 6, and Batrachoididae with 7 endemic species. In the Red Sea at least 170 of the more than 1100 species are endemic. The WIO region is also home to a large human population, representing a wide range of ethnic and cultural backgrounds. The area includes the countries of South Africa, Mozambique, Tanzania, Kenya, Somalia, Eritrea, Sudan, Egypt, Israel, Jordan, Saudi Arabia, Yemen, Oman, United Arab Emirates, Qatar, Bahrain, Kuwait, Iraq, Iran, Pakistan, India and Sri Lanka, as well as the many island nations and territories. Many of the people living in coastal areas are dependent on fish catches and other marine resources for both sustenance and often a livelihood, as highly diversified artisanal fisheries make up the bulk of the fishing effort in the region. And, as elsewhere in the world, many of the fish resources have been compromised by commercial interests (including those of other countries), often leaving fish stocks in a poor state. This book has a number of purposes, all of which coalesce around providing users with a better understanding of the area’s fishes and their environment. Accordingly, it includes a number of background chapters covering subjects as diverse as the oceanography of the region, and the history and evolution of the bony fishes. In recent years genetic analysis has proved to be a powerful tool for taxonomists. In many instances molecular results have caused taxonomists to rethink both the definitions of certain taxa and the interrelationships of taxa. In some instances, what were long considered cohesive (monophyletic) taxa were found to include groups of fishes that are in fact not closely related (paraphyletic), while in other instances taxa thought to be distinct were found not to be, meriting their merging with other existing taxa. At times, long-accepted family groups have been divided into two or more distinct families, or separate families have been combined into a single one. Where possible such changes in our understanding of the relationships of fishes are reflected in these volumes. Where some contributors have taken a more conservative approach by awaiting more research and not adopting these changes, alternative taxonomies are noted (see also the introductory chapter on Naming organisms and determining their relationships). For each species in the book, the literature pertinent to that species in the WIO is given: the original species description reference, synonyms for the region and other important taxonomic and biological references. For many commercially important species or fishes of interest to anglers there is additional information on life history, size and capture, and for some but not all species, their IUCN conservation status if Near Threatened, Vulnerable, Endangered or Critically Endangered (in the first instance, valid at the time of writing. See www.iucnredlist.org for current information. Note: we have not included the IUCN conservation status where species are of Least Concern or Data Deficient). Most species are illustrated with photographs, drawings or paintings. Colour photographs and paintings are provided on plates for each volume. , 1st Edition
- Full Text:
- Date Issued: 2022
Comparative avifaunal richness and diversity in invasive Acacia dealbata patches and adjacent montane grasslands
- Seath, Jessica, Shackleton, Charles M
- Authors: Seath, Jessica , Shackleton, Charles M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406585 , vital:70287 , xlink:href="https://hdl.handle.net/10520/ejc-afzoo_v57_i1_a12"
- Description: Abstract Invasive alien species are regarded as the second greatest threat to biodiversity globally. Yet, at a local scale their effects may vary, underlying the requirement for more local-scale studies across taxa and settings. Here we consider the effects of an alien invasive tree (Acacia dealbata, 5–8 m tall) on avifaunal numbers, richness and diversity in A. dealbata patches of three sizes relative to adjacent montane grasslands. Analysis of historical aerial photographs showed that A. dealbata first occurred in the area in the late 1930s/early 1940s and has continued to spread, despite some efforts by the landowner to keep it in check. It now covers approximately 11% of the site. This has provided habitat for a number of bird species more characteristic of wooded vegetation types. The number, richness and diversity of birds were greater in A. dealbata patches than the adjacent grasslands of equivalent size. These measures increased with increasing patch size, but more rapidly for A. dealbata patches than grassland ones. Only six of the 48 species of birds recorded were common between the two vegetation types. The most common feeding guild in the A. dealbata patches was insectivores, whereas in the grasslands it was omnivores. Although the invasion of A. dealbata has added to the habitat diversity of the area, thereby facilitating increased avifaunal diversity, if it continues to spread, then the populations and perhaps richness of grassland birds are likely to be negatively affected.
- Full Text:
- Date Issued: 2022
- Authors: Seath, Jessica , Shackleton, Charles M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406585 , vital:70287 , xlink:href="https://hdl.handle.net/10520/ejc-afzoo_v57_i1_a12"
- Description: Abstract Invasive alien species are regarded as the second greatest threat to biodiversity globally. Yet, at a local scale their effects may vary, underlying the requirement for more local-scale studies across taxa and settings. Here we consider the effects of an alien invasive tree (Acacia dealbata, 5–8 m tall) on avifaunal numbers, richness and diversity in A. dealbata patches of three sizes relative to adjacent montane grasslands. Analysis of historical aerial photographs showed that A. dealbata first occurred in the area in the late 1930s/early 1940s and has continued to spread, despite some efforts by the landowner to keep it in check. It now covers approximately 11% of the site. This has provided habitat for a number of bird species more characteristic of wooded vegetation types. The number, richness and diversity of birds were greater in A. dealbata patches than the adjacent grasslands of equivalent size. These measures increased with increasing patch size, but more rapidly for A. dealbata patches than grassland ones. Only six of the 48 species of birds recorded were common between the two vegetation types. The most common feeding guild in the A. dealbata patches was insectivores, whereas in the grasslands it was omnivores. Although the invasion of A. dealbata has added to the habitat diversity of the area, thereby facilitating increased avifaunal diversity, if it continues to spread, then the populations and perhaps richness of grassland birds are likely to be negatively affected.
- Full Text:
- Date Issued: 2022
Constellations, technicality, iconisation and Eskom: A case from South Africa’s Business Day
- Siebörger, Ian, Adendorff, Ralph D
- Authors: Siebörger, Ian , Adendorff, Ralph D
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/385350 , vital:68010 , xlink:href="https://doi.org/10.2989/16073614.2022.2040369"
- Description: This article uses Legitimation Code Theory (LCT) and systemic functional linguistics (SFL) to explore interactions between various resources for building economic and political knowledge in a 2015 article from Business Day, a South African newspaper, concerning the country’s energy crisis. We use LCT to observe how three constellations are built in the article: a ‘developmental state’ constellation; a ‘neo-liberal’ constellation; and another underarticulated constellation that selectively draws ideas from both the preceding constellations. These constellations are built through the unfolding of the text using various linguistic resources, which we describe using SFL, including technicality and iconisation. We identify instances where words are charged with both ideational and axiological meaning concurrently, challenging existing understandings of the process of iconisation.
- Full Text:
- Date Issued: 2022
- Authors: Siebörger, Ian , Adendorff, Ralph D
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/385350 , vital:68010 , xlink:href="https://doi.org/10.2989/16073614.2022.2040369"
- Description: This article uses Legitimation Code Theory (LCT) and systemic functional linguistics (SFL) to explore interactions between various resources for building economic and political knowledge in a 2015 article from Business Day, a South African newspaper, concerning the country’s energy crisis. We use LCT to observe how three constellations are built in the article: a ‘developmental state’ constellation; a ‘neo-liberal’ constellation; and another underarticulated constellation that selectively draws ideas from both the preceding constellations. These constellations are built through the unfolding of the text using various linguistic resources, which we describe using SFL, including technicality and iconisation. We identify instances where words are charged with both ideational and axiological meaning concurrently, challenging existing understandings of the process of iconisation.
- Full Text:
- Date Issued: 2022
Cultural Seascapes in the ‘Sea of Calms’ and La Restinga Coast
- De la Cruz-Modino, Raquel, Piñeiro-Corbeira, Cristina, Aswani, Shankar, González-Cruz, Carla, Domínguez, David, Ordóñez García, Paula, Santana-Talavera, Agustín, Pascual-Fernández, José
- Authors: De la Cruz-Modino, Raquel , Piñeiro-Corbeira, Cristina , Aswani, Shankar , González-Cruz, Carla , Domínguez, David , Ordóñez García, Paula , Santana-Talavera, Agustín , Pascual-Fernández, José
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/391319 , vital:68641 , ISBN 978-3-031-07289-5 , https://doi.org/10.1007/978-3-031-07289-5
- Description: El Hierro has been characterized by the balance between human development and environmental sustainability. The island was historically far from the mass tourism developments dominant on the other Canary Islands. Tourism accommodations in El Hierro are few compared to more developed coastal areas in the Archipelago, and recreational activities are mainly linked to cultural and natural sites and resources. This chapter focuses on La Restinga fishing village and its coasts, where the ‘Sea of Calms’ and one multiple-use Marine Reserve (MR) are located, both of which became popular over the last decade. The tourist development experience has promoted a new way of looking at the sea and conceptualizing its habitats and populations. In 2014, after the submarine volcano eruption occurred in 2011, we estimated that at least 25,391 dives had been carried out in the diving spots established by the MR and other diving sites close to La Restinga. Despite the difficulties experienced after the volcano eruption, a unique imaginaire has been consolidated, thanks to the image of the island's exclusive nature and iconic elements. In addition, the rapid recovery of the destination is an excellent example of how the tourism system can adapt and incorporate unexpected events such as volcanic eruptions.
- Full Text:
- Date Issued: 2022
- Authors: De la Cruz-Modino, Raquel , Piñeiro-Corbeira, Cristina , Aswani, Shankar , González-Cruz, Carla , Domínguez, David , Ordóñez García, Paula , Santana-Talavera, Agustín , Pascual-Fernández, José
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/391319 , vital:68641 , ISBN 978-3-031-07289-5 , https://doi.org/10.1007/978-3-031-07289-5
- Description: El Hierro has been characterized by the balance between human development and environmental sustainability. The island was historically far from the mass tourism developments dominant on the other Canary Islands. Tourism accommodations in El Hierro are few compared to more developed coastal areas in the Archipelago, and recreational activities are mainly linked to cultural and natural sites and resources. This chapter focuses on La Restinga fishing village and its coasts, where the ‘Sea of Calms’ and one multiple-use Marine Reserve (MR) are located, both of which became popular over the last decade. The tourist development experience has promoted a new way of looking at the sea and conceptualizing its habitats and populations. In 2014, after the submarine volcano eruption occurred in 2011, we estimated that at least 25,391 dives had been carried out in the diving spots established by the MR and other diving sites close to La Restinga. Despite the difficulties experienced after the volcano eruption, a unique imaginaire has been consolidated, thanks to the image of the island's exclusive nature and iconic elements. In addition, the rapid recovery of the destination is an excellent example of how the tourism system can adapt and incorporate unexpected events such as volcanic eruptions.
- Full Text:
- Date Issued: 2022
Dark brown three-legged round African clay pot
- Date: 2022 , 2022-10-05
- Subjects: Bam, Brigalia , Pottery, African
- Language: English
- Type: realia
- Identifier: http://hdl.handle.net/10948/56874 , vital:57197
- Description: Dark brown round African clay pot, with three legs and a shield pattern. Interior of pot is cream coloured. , Donated/gifted to Nelson Mandela University Archives , Forms part of: Brigalia Bam collection
- Full Text: false
- Date Issued: 2022
- Date: 2022 , 2022-10-05
- Subjects: Bam, Brigalia , Pottery, African
- Language: English
- Type: realia
- Identifier: http://hdl.handle.net/10948/56874 , vital:57197
- Description: Dark brown round African clay pot, with three legs and a shield pattern. Interior of pot is cream coloured. , Donated/gifted to Nelson Mandela University Archives , Forms part of: Brigalia Bam collection
- Full Text: false
- Date Issued: 2022
Decoration of glass wool with zinc (II) phthalocyanine for the photocatalytic transformation of methyl orange
- Sindelo, Azole, Britton, Jonathan, Lanterna, Anabel E, Scaiano, Juan C, Nyokong, Tebello
- Authors: Sindelo, Azole , Britton, Jonathan , Lanterna, Anabel E , Scaiano, Juan C , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295742 , vital:57374 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114127"
- Description: Zinc phthalocyanines containing one (mono carboxy phenoxy, ZnMCPPc), four (tetra carboxy phenoxy, ZnTCPPc), and eight (tetra isophthalic acid, ZnTIPAPc) carboxyl groups were covalently conjugated to amine-functionalized glass wool (GW). The GW-Pcs were characterized and evaluated for singlet oxygen generation. The photocatalytic efficiencies of the GW-Pcs were assessed using methyl orange. Glass wool alone and the modified conjugates exhibited low to no degradation of methyl orange in the dark. The improved catalytic rate was observed for GW-ZnMCPPc and GW-ZnTCPPc compared to GW-ZnTIPAPc due to the latter's lower singlet oxygen quantum yield generation. In addition, the modified glass wool was recyclable, making it suitable candidates for future environmental applications.
- Full Text:
- Date Issued: 2022
- Authors: Sindelo, Azole , Britton, Jonathan , Lanterna, Anabel E , Scaiano, Juan C , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295742 , vital:57374 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114127"
- Description: Zinc phthalocyanines containing one (mono carboxy phenoxy, ZnMCPPc), four (tetra carboxy phenoxy, ZnTCPPc), and eight (tetra isophthalic acid, ZnTIPAPc) carboxyl groups were covalently conjugated to amine-functionalized glass wool (GW). The GW-Pcs were characterized and evaluated for singlet oxygen generation. The photocatalytic efficiencies of the GW-Pcs were assessed using methyl orange. Glass wool alone and the modified conjugates exhibited low to no degradation of methyl orange in the dark. The improved catalytic rate was observed for GW-ZnMCPPc and GW-ZnTCPPc compared to GW-ZnTIPAPc due to the latter's lower singlet oxygen quantum yield generation. In addition, the modified glass wool was recyclable, making it suitable candidates for future environmental applications.
- Full Text:
- Date Issued: 2022
Design and fabrication of electrochemical sensor based on molecularly imprinted polymer loaded onto silver nanoparticles for the detection of 17-β-Estradiol
- Regasa, Melkamu Biyana, Nyokong, Tebello
- Authors: Regasa, Melkamu Biyana , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300287 , vital:57913 , xlink:href="https://doi.org/10.1002/jmr.2978"
- Description: In this research report, we prepared an electrochemical sensor based on the molecularly imprinted poly(p-aminophenol) supported by silver nanoparticles capped with 2-mercaptobenzoxazole for the selective and sensitive detection of endocrine disrupting 17-β-estradiol (E2). The electropolymerization of the functional monomer prepared the proposed molecularly imprinted polymer (MIP) composite-based sensor in the presence of E2 as a template. The recognition materials were characterized using Fourier transform infrared, cyclic voltammetry (CV), square wave voltammetry (SWV), scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray powder diffraction techniques. The electrochemical measurements were performed by employing both CV and SWV methods. We did the optimization of critical parameters affecting the sensor performances through the experimental design and verification. The developed sensor showed a linear range from 10 pM to 100 nM with the calculated quantification and detection limits of 1.86 and 6.19 pM, respectively. The incorporation of AgNP with high electrical conductivity into the MIP matrix enhanced the sensor's performance. Furthermore, the sensor was applied to determine E2 in real water samples without any sample preconcentration steps to achieve the percent recovery of 91.87% to 98.36% and acceptable reusability and storage stability performances.
- Full Text:
- Date Issued: 2022
- Authors: Regasa, Melkamu Biyana , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300287 , vital:57913 , xlink:href="https://doi.org/10.1002/jmr.2978"
- Description: In this research report, we prepared an electrochemical sensor based on the molecularly imprinted poly(p-aminophenol) supported by silver nanoparticles capped with 2-mercaptobenzoxazole for the selective and sensitive detection of endocrine disrupting 17-β-estradiol (E2). The electropolymerization of the functional monomer prepared the proposed molecularly imprinted polymer (MIP) composite-based sensor in the presence of E2 as a template. The recognition materials were characterized using Fourier transform infrared, cyclic voltammetry (CV), square wave voltammetry (SWV), scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray powder diffraction techniques. The electrochemical measurements were performed by employing both CV and SWV methods. We did the optimization of critical parameters affecting the sensor performances through the experimental design and verification. The developed sensor showed a linear range from 10 pM to 100 nM with the calculated quantification and detection limits of 1.86 and 6.19 pM, respectively. The incorporation of AgNP with high electrical conductivity into the MIP matrix enhanced the sensor's performance. Furthermore, the sensor was applied to determine E2 in real water samples without any sample preconcentration steps to achieve the percent recovery of 91.87% to 98.36% and acceptable reusability and storage stability performances.
- Full Text:
- Date Issued: 2022
Development and in vitro biological studies of polymer-based wound dressings with a high haemostatic ability for the management of wounds
- Nqoro, Xhamla https://orcid.org/0000-0002-2065-3629
- Authors: Nqoro, Xhamla https://orcid.org/0000-0002-2065-3629
- Date: 2022
- Subjects: Wound healing , Surgical wound infections , Wound treatment equipment industry
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27970 , vital:71404
- Description: Wounds are usually accompanied by complications such as excessive bleeding and bacteria invasion. The design of wound dressings that rapidly stop excessive bleeding and inhibit bacterial invasion is crucial to promoting accelerated wound healing. To meet the abovementioned requirements in wound dressings, topical gels were prepared from sodium alginate SA and carboxymethylcellulose CMC. The wound dressings were loaded with an antifibrinolytic agent, tranexamic acid TA, essential oils, and a variety of metal-based nanoparticles, and carbon-based biomaterials. The scanning electron microscopy SEM and X-ray diffraction XRD confirmed the successful formation of the nanoparticles. The prepared formulations exhibited in vitro drug release kinetics that best fitted with the Korsmeyer-Peppas model. These gels exhibited good spreadability and viscosity, showing a shear-thinning behaviour with pH between 6.7 and 7.3, signifying suitability for skin application and ease of application. The prepared topical gels exhibited significant antibacterial effects against gram-negative and gram-positive strains of bacteria. SA EO-based formulations showed high antibacterial activity across all bacterial strains, followed by SA-based formulations compared to CMC-based formulations, which exhibited moderate antibacterial activity. Moreover, the prepared gels showed good cytocompatibility, promoted cell proliferation, and exhibited 80 percent wound closure on day 3 compared to the untreated group, which showed a 38 percent wound reduction in vitro. Excellent blood clotting properties were observed with CMC-based gels compared to other formulations. However, all the prepared formulations exhibited outstanding blood clotting ability compared to the control, showing that they can promote rapid blood coagulation. The features presented by the prepared gels reveal that they are suitable for rapid wound healing , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022
- Authors: Nqoro, Xhamla https://orcid.org/0000-0002-2065-3629
- Date: 2022
- Subjects: Wound healing , Surgical wound infections , Wound treatment equipment industry
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27970 , vital:71404
- Description: Wounds are usually accompanied by complications such as excessive bleeding and bacteria invasion. The design of wound dressings that rapidly stop excessive bleeding and inhibit bacterial invasion is crucial to promoting accelerated wound healing. To meet the abovementioned requirements in wound dressings, topical gels were prepared from sodium alginate SA and carboxymethylcellulose CMC. The wound dressings were loaded with an antifibrinolytic agent, tranexamic acid TA, essential oils, and a variety of metal-based nanoparticles, and carbon-based biomaterials. The scanning electron microscopy SEM and X-ray diffraction XRD confirmed the successful formation of the nanoparticles. The prepared formulations exhibited in vitro drug release kinetics that best fitted with the Korsmeyer-Peppas model. These gels exhibited good spreadability and viscosity, showing a shear-thinning behaviour with pH between 6.7 and 7.3, signifying suitability for skin application and ease of application. The prepared topical gels exhibited significant antibacterial effects against gram-negative and gram-positive strains of bacteria. SA EO-based formulations showed high antibacterial activity across all bacterial strains, followed by SA-based formulations compared to CMC-based formulations, which exhibited moderate antibacterial activity. Moreover, the prepared gels showed good cytocompatibility, promoted cell proliferation, and exhibited 80 percent wound closure on day 3 compared to the untreated group, which showed a 38 percent wound reduction in vitro. Excellent blood clotting properties were observed with CMC-based gels compared to other formulations. However, all the prepared formulations exhibited outstanding blood clotting ability compared to the control, showing that they can promote rapid blood coagulation. The features presented by the prepared gels reveal that they are suitable for rapid wound healing , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022
Double stimulation and transformative agency for leadership development of school learners in Southern Africa
- Authors: Grant, Carolyn
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281035 , vital:55685 , xlink:href="https://doi.org/10.1080/14681366.2020.1805495"
- Description: Learners, because of their minor status, are a virtual absence in everyday school leadership work, particularly on the African continent. School leadership, therefore, continues to be misconceived as an adult phenomenon. Framed by Cultural Historical Activity Theory, this paper reports on a Southern African Higher Education studythat engages with the Vygotskian principle of ‘double stimulation’ and its relationship to transformative agency in the context of a school-based learner leadership development initiative. One school change project was purposively selected as the case, and data were drawn from a postgraduate student research report and self-reflective journal. Drawing on the Sannino model of double stimulation, the paper explores the phases of double stimulation as well as instances of transformative agency evident in the data, and speculates about the relationship between double stimulation and transformative agency in the leadership development of learners.
- Full Text:
- Date Issued: 2022
- Authors: Grant, Carolyn
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281035 , vital:55685 , xlink:href="https://doi.org/10.1080/14681366.2020.1805495"
- Description: Learners, because of their minor status, are a virtual absence in everyday school leadership work, particularly on the African continent. School leadership, therefore, continues to be misconceived as an adult phenomenon. Framed by Cultural Historical Activity Theory, this paper reports on a Southern African Higher Education studythat engages with the Vygotskian principle of ‘double stimulation’ and its relationship to transformative agency in the context of a school-based learner leadership development initiative. One school change project was purposively selected as the case, and data were drawn from a postgraduate student research report and self-reflective journal. Drawing on the Sannino model of double stimulation, the paper explores the phases of double stimulation as well as instances of transformative agency evident in the data, and speculates about the relationship between double stimulation and transformative agency in the leadership development of learners.
- Full Text:
- Date Issued: 2022
Drowning in data, thirsty for information and starved for understanding: A biodiversity information hub for cooperative environmental monitoring in South Africa
- MacFadyen, Sandra, Allsopp, Nicky, Altwegg, Res, Archibald, Sally, Botha, Judith, Bradshaw, Karen, Carruthers, Jane, De Klerk, Helen, de Vos, Alta, Distiller, Greg, Foord, Stefan, Freitag-Ronaldson, Stefanie, Gibbs, Richard, Hamer, Michelle, Landi, Pietro, MacFayden, Duncan, Manuel, Jeffrey, Midgley, Guy, Moncrieff, Glenn, Munch, Zahn, Mutanga, Onisimo, Sershen, Nenguda, Rendani, Ngwenya, Mzabalazo, Parker, Daniel, Peel, Mike, Power, John, Pretorius, Joachim, Ramdhani, Syd, Robertson, Mark, Rushworth, Ian, Skowno, Andrew, Slingsby, Jasper, Turner, Andrew, Visser, Vernon, van Wageningen, Gerhard, Hui, Cang
- Authors: MacFadyen, Sandra , Allsopp, Nicky , Altwegg, Res , Archibald, Sally , Botha, Judith , Bradshaw, Karen , Carruthers, Jane , De Klerk, Helen , de Vos, Alta , Distiller, Greg , Foord, Stefan , Freitag-Ronaldson, Stefanie , Gibbs, Richard , Hamer, Michelle , Landi, Pietro , MacFayden, Duncan , Manuel, Jeffrey , Midgley, Guy , Moncrieff, Glenn , Munch, Zahn , Mutanga, Onisimo , Sershen , Nenguda, Rendani , Ngwenya, Mzabalazo , Parker, Daniel , Peel, Mike , Power, John , Pretorius, Joachim , Ramdhani, Syd , Robertson, Mark , Rushworth, Ian , Skowno, Andrew , Slingsby, Jasper , Turner, Andrew , Visser, Vernon , van Wageningen, Gerhard , Hui, Cang
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/415624 , vital:71271 , xlink:href="https://doi.org/10.1016/j.biocon.2022.109736"
- Description: The world is firmly cemented in a notitian age (Latin: notitia, meaning data) – drowning in data, yet thirsty for information and the synthesis of knowledge into understanding. As concerns over biodiversity declines escalate, the volume, diversity and speed at which new environmental and ecological data are generated has increased exponentially. Data availability primes the research and discovery engine driving biodiversity conservation. South Africa (SA) is poised to become a world leader in biodiversity conservation. However, continent-wide resource limitations hamper the establishment of inclusive technologies and robust platforms and tools for biodiversity informatics. In this perspectives piece, we bring together the opinions of 37 co-authors from 20 different departments, across 10 SA universities, 7 national and provincial conservation research agencies, and various institutes and private conservation, research and management bodies, to develop a way forward for biodiversity informatics in SA. We propose the development of a SA Biodiversity Informatics Hub and describe the essential components necessary for its design, implementation and sustainability. We emphasise the importance of developing a culture of cooperation, collaboration and interoperability among custodians of biodiversity data to establish operational workflows for data synthesis. However, our biggest challenges are misgivings around data sharing and multidisciplinary collaboration.
- Full Text:
- Date Issued: 2022
- Authors: MacFadyen, Sandra , Allsopp, Nicky , Altwegg, Res , Archibald, Sally , Botha, Judith , Bradshaw, Karen , Carruthers, Jane , De Klerk, Helen , de Vos, Alta , Distiller, Greg , Foord, Stefan , Freitag-Ronaldson, Stefanie , Gibbs, Richard , Hamer, Michelle , Landi, Pietro , MacFayden, Duncan , Manuel, Jeffrey , Midgley, Guy , Moncrieff, Glenn , Munch, Zahn , Mutanga, Onisimo , Sershen , Nenguda, Rendani , Ngwenya, Mzabalazo , Parker, Daniel , Peel, Mike , Power, John , Pretorius, Joachim , Ramdhani, Syd , Robertson, Mark , Rushworth, Ian , Skowno, Andrew , Slingsby, Jasper , Turner, Andrew , Visser, Vernon , van Wageningen, Gerhard , Hui, Cang
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/415624 , vital:71271 , xlink:href="https://doi.org/10.1016/j.biocon.2022.109736"
- Description: The world is firmly cemented in a notitian age (Latin: notitia, meaning data) – drowning in data, yet thirsty for information and the synthesis of knowledge into understanding. As concerns over biodiversity declines escalate, the volume, diversity and speed at which new environmental and ecological data are generated has increased exponentially. Data availability primes the research and discovery engine driving biodiversity conservation. South Africa (SA) is poised to become a world leader in biodiversity conservation. However, continent-wide resource limitations hamper the establishment of inclusive technologies and robust platforms and tools for biodiversity informatics. In this perspectives piece, we bring together the opinions of 37 co-authors from 20 different departments, across 10 SA universities, 7 national and provincial conservation research agencies, and various institutes and private conservation, research and management bodies, to develop a way forward for biodiversity informatics in SA. We propose the development of a SA Biodiversity Informatics Hub and describe the essential components necessary for its design, implementation and sustainability. We emphasise the importance of developing a culture of cooperation, collaboration and interoperability among custodians of biodiversity data to establish operational workflows for data synthesis. However, our biggest challenges are misgivings around data sharing and multidisciplinary collaboration.
- Full Text:
- Date Issued: 2022
Electrocatalytic activity of benzothiazole substituted cobalt phthalocyanine in the presence of detonation nanodiamonds
- Ncwane, Lunathi, Mpeta, Lekhetho S, Nyokong, Tebello
- Authors: Ncwane, Lunathi , Mpeta, Lekhetho S , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295753 , vital:57375 , xlink:href="https://doi.org/10.1016/j.diamond.2022.109319"
- Description: This work reports on the synthesis and electrochemical sensing properties of benzothiazole substituted cobalt phthalocyanine (CoPc) when π-π stacked on detonation nanodiamonds (to form CoPc-DNDs(ππ). The synthesized materials were characterized using UV–visible, mass, Fourier transform infrared, and Raman spectroscopies as well as transmission electron microscopy and dynamic light scattering. The electrochemical studies were conducted using cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. Hydrazine was utilized as an analyte of interest, due to its mutagenic and carcinogenic effects. Glassy carbon electrodes (GCE) were modified with DNDs, CoPc, and CoPc-DNDs(ππ) represented as GCE/DNDs, GCE/CoPc and GCE/ CoPc-DNDs(ππ). GCE was also modified sequential addition of the CoPc and DNDs onto the GCE, represented as GCE/CoPc-DNDs(seq) when CoPc is placed before DNDs on the electrode and GCE/DNDs-CoPc(seq) when DNDs are placed before CoPc, where seq represents sequential. GCE/CoPc-DNDs(ππ) electrode gave better results in terms of limit of detection (1.68 μM), sensitivity (9.59 μA.mM−1) and catalytic rate constant (1.25 × 106 M−1 s−1).
- Full Text:
- Date Issued: 2022
- Authors: Ncwane, Lunathi , Mpeta, Lekhetho S , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295753 , vital:57375 , xlink:href="https://doi.org/10.1016/j.diamond.2022.109319"
- Description: This work reports on the synthesis and electrochemical sensing properties of benzothiazole substituted cobalt phthalocyanine (CoPc) when π-π stacked on detonation nanodiamonds (to form CoPc-DNDs(ππ). The synthesized materials were characterized using UV–visible, mass, Fourier transform infrared, and Raman spectroscopies as well as transmission electron microscopy and dynamic light scattering. The electrochemical studies were conducted using cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. Hydrazine was utilized as an analyte of interest, due to its mutagenic and carcinogenic effects. Glassy carbon electrodes (GCE) were modified with DNDs, CoPc, and CoPc-DNDs(ππ) represented as GCE/DNDs, GCE/CoPc and GCE/ CoPc-DNDs(ππ). GCE was also modified sequential addition of the CoPc and DNDs onto the GCE, represented as GCE/CoPc-DNDs(seq) when CoPc is placed before DNDs on the electrode and GCE/DNDs-CoPc(seq) when DNDs are placed before CoPc, where seq represents sequential. GCE/CoPc-DNDs(ππ) electrode gave better results in terms of limit of detection (1.68 μM), sensitivity (9.59 μA.mM−1) and catalytic rate constant (1.25 × 106 M−1 s−1).
- Full Text:
- Date Issued: 2022
Electrochemical detection of human epidermal growth factor receptor 2 using an aptamer on cobalt phthalocyanines–Cerium oxide nanoparticle conjugate
- Centane, Sixolile, Mgidlana, Sithi, Openda, Yolanda, Nyokong, Tebello
- Authors: Centane, Sixolile , Mgidlana, Sithi , Openda, Yolanda , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/299835 , vital:57859 , xlink:href="https://doi.org/10.1016/j.bioelechem.2022.108146"
- Description: The role of the biointerface design towards the development of an impedimetric biosensor for the electrochemical detection of human epidermal growth factor receptor 2 (HER2) is investigated. Two novel cobalt phthalocyanines: cobalt tetraphenyl acetic acid phthalocyanine and cobalt tetraphenyl propionic acid phthalocyanine are compared as signal amplifiers and immobilization platforms of the HB5 aptamer towards the electrochemical detection of HER2. In addition, the phthalocyanines are coupled with the metal based cerium oxide nanoparticles. The efficiency of each electrode modification step and the performance of the constructed aptasensors were assessed by impedance spectroscopy. The aptasensors showed very low limit of detection values (all less than 0.2 ng/mL) with high sensitivity and stability. Furthermore, the aptasensors showed very good performance even in human serum samples. Considering these results, the aptasensors demonstrate great potential for improved monitoring of human epidermal growth factor receptor 2 levels for the management of breast cancers.
- Full Text:
- Date Issued: 2022
- Authors: Centane, Sixolile , Mgidlana, Sithi , Openda, Yolanda , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/299835 , vital:57859 , xlink:href="https://doi.org/10.1016/j.bioelechem.2022.108146"
- Description: The role of the biointerface design towards the development of an impedimetric biosensor for the electrochemical detection of human epidermal growth factor receptor 2 (HER2) is investigated. Two novel cobalt phthalocyanines: cobalt tetraphenyl acetic acid phthalocyanine and cobalt tetraphenyl propionic acid phthalocyanine are compared as signal amplifiers and immobilization platforms of the HB5 aptamer towards the electrochemical detection of HER2. In addition, the phthalocyanines are coupled with the metal based cerium oxide nanoparticles. The efficiency of each electrode modification step and the performance of the constructed aptasensors were assessed by impedance spectroscopy. The aptasensors showed very low limit of detection values (all less than 0.2 ng/mL) with high sensitivity and stability. Furthermore, the aptasensors showed very good performance even in human serum samples. Considering these results, the aptasensors demonstrate great potential for improved monitoring of human epidermal growth factor receptor 2 levels for the management of breast cancers.
- Full Text:
- Date Issued: 2022
Enacting Environmental Ethics Education for Wildlife Conservation using an Afrophilic ‘Philosophy for Children’approach
- Authors: Bhurekeni, John
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/389821 , vital:68487 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/224689"
- Description: Environmental Ethics Education has in recent years emerged as a critical tool for wildlife conservation research. Despite this, Environmental Ethics Education is paradoxically predominated by traditional forms of western science such as the concept of the Anthropocene which appears to exclude aspects of African life-worlds where the natural environment is considered a heritage component and is linked to onto-ethical understandings of human existence. The purpose of this study is to explore how African heritage-based knowledges and practices are understood by children who identify and understand the relevance of their totems and taboos associated with them, in relation to wildlife conservation. The study from which this paper is derived utilised formative interventionist methodology complemented by a multi-voiced decolonial approach to explore whether children-participants aged 8 to 11 years understand the purposes of their totems and associated taboos. To achieve this I used an Afrophilic Philosophy for Children pedagogical approach, which foregrounds dialogical learning and development of critical reflexive thinking skills. Emerging findings indicated that children associated their totems and connected taboos as tools for protection against environmental pollution and for minimising resource over-extraction. Findings further demonstrated improved learner agency and development of ethical reasoning among children. As participants’ respect for environmental conservation and sustainability was informed by the significance placed on their totems, I recommend the need for schools to develop generative curricula that take seriously context-based solutions to environmental problems. Future research should also consider understanding environmental conservation issues from a context-based perspective, which can inform existing heritage practices and pedagogies.
- Full Text:
- Date Issued: 2022
- Authors: Bhurekeni, John
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/389821 , vital:68487 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/224689"
- Description: Environmental Ethics Education has in recent years emerged as a critical tool for wildlife conservation research. Despite this, Environmental Ethics Education is paradoxically predominated by traditional forms of western science such as the concept of the Anthropocene which appears to exclude aspects of African life-worlds where the natural environment is considered a heritage component and is linked to onto-ethical understandings of human existence. The purpose of this study is to explore how African heritage-based knowledges and practices are understood by children who identify and understand the relevance of their totems and taboos associated with them, in relation to wildlife conservation. The study from which this paper is derived utilised formative interventionist methodology complemented by a multi-voiced decolonial approach to explore whether children-participants aged 8 to 11 years understand the purposes of their totems and associated taboos. To achieve this I used an Afrophilic Philosophy for Children pedagogical approach, which foregrounds dialogical learning and development of critical reflexive thinking skills. Emerging findings indicated that children associated their totems and connected taboos as tools for protection against environmental pollution and for minimising resource over-extraction. Findings further demonstrated improved learner agency and development of ethical reasoning among children. As participants’ respect for environmental conservation and sustainability was informed by the significance placed on their totems, I recommend the need for schools to develop generative curricula that take seriously context-based solutions to environmental problems. Future research should also consider understanding environmental conservation issues from a context-based perspective, which can inform existing heritage practices and pedagogies.
- Full Text:
- Date Issued: 2022
Enhanced mitochondria destruction on MCF-7 and HeLa cell lines in vitro using triphenyl-phosphonium-labelled phthalocyanines in ultrasound-assisted photodynamic therapy activity
- Nene, Lindokuhle Cindy, Magadla, Aviwe, Nyokong, Tebello
- Authors: Nene, Lindokuhle Cindy , Magadla, Aviwe , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295766 , vital:57376 , xlink:href="https://doi.org/10.1016/j.jphotobiol.2022.112553"
- Description: This work reports on the reactive oxygen species (ROS) generation and the therapeutic activities of new triphenyl-phosphonium-labelled phthalocyanines (Pcs), the 2,9,16,23-tetrakis(N-(N-butyl-4-triphenyl-phosphonium)- pyridine-4-yloxy) Zn(II) Pc (3) and 2,9,16,23-tetrakis-(N-(N-butyl-4-triphenyl-phosphonium)-morpholino) Zn(II) Pc (4) upon exposure to light, ultrasound and the combination of light and ultrasound. Two types of ROS were detected: the singlet oxygen (1O2) and hydroxyl radicals. For light irradiations, only the 1O2 was detected. An increase in the ROS generation was observed for samples treated with the combination of light and ultrasound compared to the light and ultrasound mono-treatments. The in vitro anticancer activity through photodynamic (PDT) and sonodynamic (SDT) therapy for the Pcs were also determined and compared to the photo-sonodynamic combination therapy (PSDT). The two cancer cell lines used for the in vitro studies included the Michigan Cancer Foundation-7 (MCF-7) breast cancer and Henrietta Lacks (HeLa) cervical cancer cell lines. The SDT treatments showed improved therapeutic efficacy on the cancer cells for both the Pcs compared to PDT. PSDT showed better therapeutic efficacy compared to both the PDT and SDT mono-treatments.
- Full Text:
- Date Issued: 2022
- Authors: Nene, Lindokuhle Cindy , Magadla, Aviwe , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295766 , vital:57376 , xlink:href="https://doi.org/10.1016/j.jphotobiol.2022.112553"
- Description: This work reports on the reactive oxygen species (ROS) generation and the therapeutic activities of new triphenyl-phosphonium-labelled phthalocyanines (Pcs), the 2,9,16,23-tetrakis(N-(N-butyl-4-triphenyl-phosphonium)- pyridine-4-yloxy) Zn(II) Pc (3) and 2,9,16,23-tetrakis-(N-(N-butyl-4-triphenyl-phosphonium)-morpholino) Zn(II) Pc (4) upon exposure to light, ultrasound and the combination of light and ultrasound. Two types of ROS were detected: the singlet oxygen (1O2) and hydroxyl radicals. For light irradiations, only the 1O2 was detected. An increase in the ROS generation was observed for samples treated with the combination of light and ultrasound compared to the light and ultrasound mono-treatments. The in vitro anticancer activity through photodynamic (PDT) and sonodynamic (SDT) therapy for the Pcs were also determined and compared to the photo-sonodynamic combination therapy (PSDT). The two cancer cell lines used for the in vitro studies included the Michigan Cancer Foundation-7 (MCF-7) breast cancer and Henrietta Lacks (HeLa) cervical cancer cell lines. The SDT treatments showed improved therapeutic efficacy on the cancer cells for both the Pcs compared to PDT. PSDT showed better therapeutic efficacy compared to both the PDT and SDT mono-treatments.
- Full Text:
- Date Issued: 2022
Enhanced Solar Efficiency via Incorporation of Plasmonic Gold Nanostructures in a Titanium Oxide/Eosin Y Dye-Sensitized Solar Cell
- Nyembe, Sanele, Chindeka, Francis, Ndlovu, Gebhu, Mkhohlakali, Andile, Nyokong, Tebello, Sikhwiyhilu, Lucy
- Authors: Nyembe, Sanele , Chindeka, Francis , Ndlovu, Gebhu , Mkhohlakali, Andile , Nyokong, Tebello , Sikhwiyhilu, Lucy
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295783 , vital:57377 , xlink:href="https://doi.org/10.3390/nano12101715"
- Description: Plasmonic gold nanoparticles significantly improved the efficiency of a TiO2 and Eosin Y based dye-sensitized solar cell from 2.4 to 6.43%. The gold nanoparticles’ sizes that were tested were 14 nm, 30 nm and 40 nm synthesized via the systematic reduction of citrate concentration using the Turkevich method. Prestine TiO2 without plasmonic gold nanoparticles yielded an efficiency of 2.4%. However, the loading of 40 nm gold nanoparticles into the TiO2 matrix yielded the highest DSSC efficiency of 6.43% compared to 30 nm (5.91%) and 14 nm (2.6%). The relatively high efficiency demonstrated by plasmonic gold nanoparticles is ascribed to light absorption/scattering, hot electron injection and plasmon-induced resonance energy transfer (PIRET), influenced by the size of the gold nanoparticles.
- Full Text:
- Date Issued: 2022
- Authors: Nyembe, Sanele , Chindeka, Francis , Ndlovu, Gebhu , Mkhohlakali, Andile , Nyokong, Tebello , Sikhwiyhilu, Lucy
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295783 , vital:57377 , xlink:href="https://doi.org/10.3390/nano12101715"
- Description: Plasmonic gold nanoparticles significantly improved the efficiency of a TiO2 and Eosin Y based dye-sensitized solar cell from 2.4 to 6.43%. The gold nanoparticles’ sizes that were tested were 14 nm, 30 nm and 40 nm synthesized via the systematic reduction of citrate concentration using the Turkevich method. Prestine TiO2 without plasmonic gold nanoparticles yielded an efficiency of 2.4%. However, the loading of 40 nm gold nanoparticles into the TiO2 matrix yielded the highest DSSC efficiency of 6.43% compared to 30 nm (5.91%) and 14 nm (2.6%). The relatively high efficiency demonstrated by plasmonic gold nanoparticles is ascribed to light absorption/scattering, hot electron injection and plasmon-induced resonance energy transfer (PIRET), influenced by the size of the gold nanoparticles.
- Full Text:
- Date Issued: 2022
Evaluation of functionalized silver and silica nanoparticles for the removal of deoxyribonucleic acid conveying antibiotics resistance genes from water
- Authors: Ezeuko, Adaora Stella
- Date: 2022
- Subjects: DNA , Silica , Water
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27765 , vital:69414
- Description: Antibiotic resistance genes ARGs are recognized as a serious public health emergency linked to extensive use of antibiotics by humans and animals as a prophylactic agent that treats and prevents infections. The occurrence of high concentrations being identified in wastewater treatment plants, rivers, etc is due to untreated effluents being discharged from households, hospitals, agriculture, and pharmaceutical industries. The application of adequate treatment techniques and material for the removal of bacteria DNA conveying ARGs from the effluents before their release to the environment cannot be overemphasized. Adsorption techniques seem to be effective due to their easy design, operation, and ability to regenerate adsorbents for use without producing toxic by-products. This concept was employed for the removal of bacteria DNA conveying ARGs from simulated aqueous solution, effluents from hospital, river and WWTPs using silver and silica metallic nanoparticles. This thesis investigated the effectiveness of metallic nanoparticles containing silver AgNPs and mesoporous silica nanoparticles MSNPs as well as magnetite Fe3O4 functionalized with 4 4hydroxyphenyl 2 262-terpyridine onto their surface, for the removal of bacteria DNA conveying antibiotic resistance genes from water samples from hospitals, river, and wastewater treatment plants WWTPs. Silver nanoparticles AgNPs of different molar concentrations 0.1M, 0.5M and 1.0 M and mesoporous silica nanoparticles MSNPs adsorbents were successfully synthesized in their original states and surface functionalization achieved by incorporating magnetite Fe3O4 and 4 4 hydroxyphenyl 2 2 6 2 terpyridine on the silver AgNPs Fe3O4 and silica MSNPs TPPY surfaces respectively. Their effectiveness as adsorbent for the removal of bacteria DNA conveying ARGs from aqueous solutions and real water/wastewater samples were investigated. The DNA uptake by the as-synthesized AgNPs and MSNPs were compared to the functionalized AgNPs Fe3O4 and MSNPsTPPY by determining the adsorbents with the highest removal efficiencies. All as synthesized and functionalized adsorbents were characterized by SEM, EDX, FTIR, XRD, UV spectroscopy and PZC before the removal process. The extraction of genomic DNA from antibiotic-resistant Enterococcus faecium and Vibrio parahaemolyticus was successfully achieved via the boiling method. Antibiotic susceptibility test was conducted using the disk diffusion method before the commencement of genomic DNA extraction. Molecular characterization via gel electrophoresis confirmed the presence of resistance genes at different base pairs. Adsorption batch experiment were investigated, and the best optimum parameters were evaluated through the influence of pH, contact time, initial DNA concentration, adsorbent dose, and competitive ions for each sorption process. The rate determining step were determined by fitting kinetic models such as Natarajan and Khalaf first order, pseudo first order, pseudo second order, Elovich model to experimental data. Also, the adsorption mechanisms determining adsorption equilibrium were investigated by fitting Freundlich, Langmuir and Sips model into the experimental data. The application of AgNPsFe3O4 nanocomposite and MSNPsTPPY for the removal of bacteria DNA demonstrated much enhancement for DNA uptake than the as-synthesized AgNPs and MSNPs materials. The incorporation of magnetite and 4 4hydroxyphenyl 2 2 6 2-terpyridine onto AgNPs and MSNPs significantly enhanced the binding affinity towards the removal the bacteria DNA via strong electrostatic attraction between the active sites on the adsorbent and the negative DNA molecules. Finally, high adsorption capacities were recorded with AgNPsFe3O4 nanocomposite and MSNPsTPPY compared to AgNPs and MSNPs with chaotropic salts. The kinetic adsorption models were mostly best fitted by the pseudo-second order and Elovich models while the adsorption equilibrium was best described by Langmuir and Sips isotherm models. MSNPs with different chaotropic salts, AgNPsFe3O4 nanocomposite and MSNPsTPPY also proved its effectiveness in DNA removal not only in the simulated aqueous solution but in three different real life water samples obtained from Cofimvaba hospital, Ndevana river and Uitenhage WWTPs. High adsorption efficiencies above 90 percent were achieved during the removal of DNA in all the three real water samples. Therefore, application of these adsorbents for the removal of bacteria DNA conveying ARGs may be a promising option that would tackle the consequences of consuming ARGs infected water globally. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022
- Authors: Ezeuko, Adaora Stella
- Date: 2022
- Subjects: DNA , Silica , Water
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27765 , vital:69414
- Description: Antibiotic resistance genes ARGs are recognized as a serious public health emergency linked to extensive use of antibiotics by humans and animals as a prophylactic agent that treats and prevents infections. The occurrence of high concentrations being identified in wastewater treatment plants, rivers, etc is due to untreated effluents being discharged from households, hospitals, agriculture, and pharmaceutical industries. The application of adequate treatment techniques and material for the removal of bacteria DNA conveying ARGs from the effluents before their release to the environment cannot be overemphasized. Adsorption techniques seem to be effective due to their easy design, operation, and ability to regenerate adsorbents for use without producing toxic by-products. This concept was employed for the removal of bacteria DNA conveying ARGs from simulated aqueous solution, effluents from hospital, river and WWTPs using silver and silica metallic nanoparticles. This thesis investigated the effectiveness of metallic nanoparticles containing silver AgNPs and mesoporous silica nanoparticles MSNPs as well as magnetite Fe3O4 functionalized with 4 4hydroxyphenyl 2 262-terpyridine onto their surface, for the removal of bacteria DNA conveying antibiotic resistance genes from water samples from hospitals, river, and wastewater treatment plants WWTPs. Silver nanoparticles AgNPs of different molar concentrations 0.1M, 0.5M and 1.0 M and mesoporous silica nanoparticles MSNPs adsorbents were successfully synthesized in their original states and surface functionalization achieved by incorporating magnetite Fe3O4 and 4 4 hydroxyphenyl 2 2 6 2 terpyridine on the silver AgNPs Fe3O4 and silica MSNPs TPPY surfaces respectively. Their effectiveness as adsorbent for the removal of bacteria DNA conveying ARGs from aqueous solutions and real water/wastewater samples were investigated. The DNA uptake by the as-synthesized AgNPs and MSNPs were compared to the functionalized AgNPs Fe3O4 and MSNPsTPPY by determining the adsorbents with the highest removal efficiencies. All as synthesized and functionalized adsorbents were characterized by SEM, EDX, FTIR, XRD, UV spectroscopy and PZC before the removal process. The extraction of genomic DNA from antibiotic-resistant Enterococcus faecium and Vibrio parahaemolyticus was successfully achieved via the boiling method. Antibiotic susceptibility test was conducted using the disk diffusion method before the commencement of genomic DNA extraction. Molecular characterization via gel electrophoresis confirmed the presence of resistance genes at different base pairs. Adsorption batch experiment were investigated, and the best optimum parameters were evaluated through the influence of pH, contact time, initial DNA concentration, adsorbent dose, and competitive ions for each sorption process. The rate determining step were determined by fitting kinetic models such as Natarajan and Khalaf first order, pseudo first order, pseudo second order, Elovich model to experimental data. Also, the adsorption mechanisms determining adsorption equilibrium were investigated by fitting Freundlich, Langmuir and Sips model into the experimental data. The application of AgNPsFe3O4 nanocomposite and MSNPsTPPY for the removal of bacteria DNA demonstrated much enhancement for DNA uptake than the as-synthesized AgNPs and MSNPs materials. The incorporation of magnetite and 4 4hydroxyphenyl 2 2 6 2-terpyridine onto AgNPs and MSNPs significantly enhanced the binding affinity towards the removal the bacteria DNA via strong electrostatic attraction between the active sites on the adsorbent and the negative DNA molecules. Finally, high adsorption capacities were recorded with AgNPsFe3O4 nanocomposite and MSNPsTPPY compared to AgNPs and MSNPs with chaotropic salts. The kinetic adsorption models were mostly best fitted by the pseudo-second order and Elovich models while the adsorption equilibrium was best described by Langmuir and Sips isotherm models. MSNPs with different chaotropic salts, AgNPsFe3O4 nanocomposite and MSNPsTPPY also proved its effectiveness in DNA removal not only in the simulated aqueous solution but in three different real life water samples obtained from Cofimvaba hospital, Ndevana river and Uitenhage WWTPs. High adsorption efficiencies above 90 percent were achieved during the removal of DNA in all the three real water samples. Therefore, application of these adsorbents for the removal of bacteria DNA conveying ARGs may be a promising option that would tackle the consequences of consuming ARGs infected water globally. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022
Evaluation of the extent of the public programming by Eastern Cape Provincial Archives and Records Services
- Tshebi, Siyathemba Mboneleli https://orcid.org/0000-0003-2833-9842
- Authors: Tshebi, Siyathemba Mboneleli https://orcid.org/0000-0003-2833-9842
- Date: 2022
- Subjects: Grahamstown (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27663 , vital:69381
- Description: Public programming initiatives are an integral part of archival operations worldwide as they support the greater use of archival records by attracting prospective users and sponsors. Public programming comprises a sequence of strategies for publicizing and marketing archives to the public, which are crucial in archival operations as they promote better use of archives and records. South African National Archives and Records. Services depends on provisions of the National Archives of South Africa Act of 1996 in its strive to promote access and use of archives as sources of information. . unknown and therefore not used to their maximal utility value, likely due to low-key and ineffective archival public programming initiatives. Consequently, the primary purpose of this research study was to evaluate the extent of public programming strategies used by the Eastern Cape Provincial Archives and Records Services (EAPARS). The study used a mixed-method, embracing qualitative and quantitative research approaches. As an integrated record-keeping framework, Record Continuum was used as a theoretical framework to guide the study. Sixteen copies of questionnaire were distributed among staff and users ECPARS. The research uncovered that ECPARS does not have specific regulations and policies on public programming, but relies on the more general provisions of the Provincial Archives and Records Services Act of 1996 as a guiding instrument in executing its public programming operations. The study further revealed various factors, such as the limited budget and inadequate staff, as key hindering factors in the smooth execution of archival public programming plans by ECPARS. The study recommends a review and update by ECPARS of how it can specifically effectively implement the provisions of the 1996 Act to the modern ways of taking public archives to the people. The research also recommends that ECPARS engage additional staff or outsourced services to strengthen its the public programming of its archival resources and services workforce for Eastern Cape Provincial Archives and Records. The study concludes that improved financial resources, use of ICTs, and coherent policy framework, and public awareness creation and education can facilitate better to acquire, widen access to use of its archives. Keyword , Thesis (MLIS) -- Faculty of Social Sciences and Humanities, 2022
- Full Text:
- Date Issued: 2022
- Authors: Tshebi, Siyathemba Mboneleli https://orcid.org/0000-0003-2833-9842
- Date: 2022
- Subjects: Grahamstown (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27663 , vital:69381
- Description: Public programming initiatives are an integral part of archival operations worldwide as they support the greater use of archival records by attracting prospective users and sponsors. Public programming comprises a sequence of strategies for publicizing and marketing archives to the public, which are crucial in archival operations as they promote better use of archives and records. South African National Archives and Records. Services depends on provisions of the National Archives of South Africa Act of 1996 in its strive to promote access and use of archives as sources of information. . unknown and therefore not used to their maximal utility value, likely due to low-key and ineffective archival public programming initiatives. Consequently, the primary purpose of this research study was to evaluate the extent of public programming strategies used by the Eastern Cape Provincial Archives and Records Services (EAPARS). The study used a mixed-method, embracing qualitative and quantitative research approaches. As an integrated record-keeping framework, Record Continuum was used as a theoretical framework to guide the study. Sixteen copies of questionnaire were distributed among staff and users ECPARS. The research uncovered that ECPARS does not have specific regulations and policies on public programming, but relies on the more general provisions of the Provincial Archives and Records Services Act of 1996 as a guiding instrument in executing its public programming operations. The study further revealed various factors, such as the limited budget and inadequate staff, as key hindering factors in the smooth execution of archival public programming plans by ECPARS. The study recommends a review and update by ECPARS of how it can specifically effectively implement the provisions of the 1996 Act to the modern ways of taking public archives to the people. The research also recommends that ECPARS engage additional staff or outsourced services to strengthen its the public programming of its archival resources and services workforce for Eastern Cape Provincial Archives and Records. The study concludes that improved financial resources, use of ICTs, and coherent policy framework, and public awareness creation and education can facilitate better to acquire, widen access to use of its archives. Keyword , Thesis (MLIS) -- Faculty of Social Sciences and Humanities, 2022
- Full Text:
- Date Issued: 2022
Fabrication of asymmetrical morpholine phthalocyanines conjugated chitosan-polyacrylonitrile nanofibers for improved photodynamic antimicrobial chemotherapy activity
- Sindelo, Azole, Mafukidze, Donovan M, Nyokong, Tebello
- Authors: Sindelo, Azole , Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229873 , vital:49719 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.102760"
- Description: The work is based on the synthesis and photodynamic antimicrobial chemotherapy (PACT) activities of neutral (1 and 2) and cationic (1Q and 2Q) morpholine substituted phthalocyanines. For applicability, these complexes were covalently linked to modified polyacrylonitrile (PAN) to form 1-PAN, 2-PAN, 1Q-PAN, and 2Q-PAN, respectively. Chitosan was conjugated to PAN (to form PAN-CS) which was then linked to the Pcs to form PAN-CS-1, PAN-CS-2, PAN-CS-1Q, and PAN-CS-2Q, respectively. Singlet oxygen quantum yields improved following the inclusion of chitosan. The PACT activities of the complexes alone and when anchored to both PAN and PAN-CS was evaluated against bacteria: S. aureus, E. coli and fungi C. albicans. Cationic phthalocyanine showed high efficacy values of >7 log reduction value for all microorganisms. These results translated into excellent bacterial colony reduction of >90% against both S. aureus and C. albicans after 1 h of photoirradiation on PAN-CS support.
- Full Text:
- Date Issued: 2022
- Authors: Sindelo, Azole , Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229873 , vital:49719 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.102760"
- Description: The work is based on the synthesis and photodynamic antimicrobial chemotherapy (PACT) activities of neutral (1 and 2) and cationic (1Q and 2Q) morpholine substituted phthalocyanines. For applicability, these complexes were covalently linked to modified polyacrylonitrile (PAN) to form 1-PAN, 2-PAN, 1Q-PAN, and 2Q-PAN, respectively. Chitosan was conjugated to PAN (to form PAN-CS) which was then linked to the Pcs to form PAN-CS-1, PAN-CS-2, PAN-CS-1Q, and PAN-CS-2Q, respectively. Singlet oxygen quantum yields improved following the inclusion of chitosan. The PACT activities of the complexes alone and when anchored to both PAN and PAN-CS was evaluated against bacteria: S. aureus, E. coli and fungi C. albicans. Cationic phthalocyanine showed high efficacy values of >7 log reduction value for all microorganisms. These results translated into excellent bacterial colony reduction of >90% against both S. aureus and C. albicans after 1 h of photoirradiation on PAN-CS support.
- Full Text:
- Date Issued: 2022
Fishes of Southern African estuaries: from species to systems
- Authors: Whitfield, Alan K
- Date: 2022
- Subjects: Estuarine fishes -- South Africa , Estuarine fishes -- Africa, Southern , Fishes -- Africa, Southern -- Identification , Estuaries -- Africa, Southern
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/97933 , vital:31512
- Description: South Africa, despite its relatively small size, is often called “a world in one country”. This phrase arises mainly from the range of oceanographic and climatic features; geological and geomorphological attributes, the diversity of human cultures, languages, races and religions; the mix of developed and developing economies; the wide range in political opinion and parties; the vast array of mineral resources; and finally, what biologists find most interesting of all, the richness of the indigenous flora and fauna. Although southern African aquatic scientists cannot boast an equivalent of the Cape Floral Kingdom, the stretch of coast between northern Namibia and southern Mozambique has a particularly rich marine biota, accounting for almost 15% of all the coastal marine species known world-wide. The richness of the ichthyofauna is due to a number of factors, including the variety of habitats around the subcontinent, ranging from coral reefs, kelp beds, sheltered bays, sandy beaches, exposed rocky shores, coastal lakes to estuaries. In addition, southern Africa is the meeting place of three great oceans and is thus the recipient of species from each of these separate faunas. In comparison to land vertebrates, the world’s fish fauna is by no means well-known, either taxonomically or with regard to the biology of the component species. Apart from the very large number of fish species (estimated to be approximately 40 000), and the difficulties posed by the medium in which they live, there are other reasons for the above state of affairs. An obvious and universal reason is the shortage of funding available for taxonomic, biological and ecological studies, with increasing emphasis being placed on aquaculture, mariculture and fisheries related work. This situation is unlikely to improve and many research institutions around the world are operating on shrinking rather than expanding budgets. The onus of responsibility to disseminate information on the world’s fish faunas therefore rests squarely on the shoulders of those who are fortunate enough to be employed in the fascinating field of ichthyology. This book, which is a major revision and expansion of an earlier monograph (Whitfield 1998), is an attempt to synthesize the available information on fishes associated with southern African estuaries and to highlight the importance of conserving these systems for both fishes and people of the region. Limited reference is made to international estuarine fish research due to space constraints and readers are referred to global ichthyological reviews in this regard. The estuaries of southern Africa (defined as south of 26°S latitude for the purposes of this book) are highly diverse, both in terms of form and functioning. They range from the clear Kosi Estuary entering the coral rich subtropical Indian Ocean waters on the east coast, to the turbid Orange River flowing into the cool upwelled waters of the Atlantic Ocean on the west coast. The estuaries of the subcontinent are fed by catchments with a wide variety of climatic and geological characteristics. For example, the cool-temperate west coast is characterized by good winter rains and relatively dry summers, whereas on the subtropical east coast the opposite rainfall pattern prevails. While most south-western Cape estuaries are fed by rivers with low suspended sediment levels, those of KwaZulu-Natal normally carry high silt loads during the rainy season. Between Mossel Bay and St Francis Bay, rainfall patterns show no distinct seasonal peak and relatively acidic waters with low nutrient levels enter a variety of estuarine types along this section of the coast. The Eastern Cape is a region of transition between the subtropical and warm-temperate biogeographic provinces, and is prone to both droughts and floods occurring during any season of the year. The southern African estuarine environment is an unpredictable and often harsh habitat to occupy, yet each year millions of larval and juvenile fishes enter and thrive in these systems. The fish species that utilize estuaries as nursery areas exhibit great diversity in size, body form, salinity tolerance, diet, habitat preference and breeding behaviour. There is also a complete gradation in terms of the dependence that each species has on the estuarine environment. These and many other issues relating to the biology and ecology of estuary-associated fish species in southern Africa are explored in the chapters to follow. It is my sincere wish that our improved knowledge of these species and their environmental requirements will contribute to the wise management and conservation of these valuable ecosystems. , 2022 Edition
- Full Text:
- Date Issued: 2022
- Authors: Whitfield, Alan K
- Date: 2022
- Subjects: Estuarine fishes -- South Africa , Estuarine fishes -- Africa, Southern , Fishes -- Africa, Southern -- Identification , Estuaries -- Africa, Southern
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/97933 , vital:31512
- Description: South Africa, despite its relatively small size, is often called “a world in one country”. This phrase arises mainly from the range of oceanographic and climatic features; geological and geomorphological attributes, the diversity of human cultures, languages, races and religions; the mix of developed and developing economies; the wide range in political opinion and parties; the vast array of mineral resources; and finally, what biologists find most interesting of all, the richness of the indigenous flora and fauna. Although southern African aquatic scientists cannot boast an equivalent of the Cape Floral Kingdom, the stretch of coast between northern Namibia and southern Mozambique has a particularly rich marine biota, accounting for almost 15% of all the coastal marine species known world-wide. The richness of the ichthyofauna is due to a number of factors, including the variety of habitats around the subcontinent, ranging from coral reefs, kelp beds, sheltered bays, sandy beaches, exposed rocky shores, coastal lakes to estuaries. In addition, southern Africa is the meeting place of three great oceans and is thus the recipient of species from each of these separate faunas. In comparison to land vertebrates, the world’s fish fauna is by no means well-known, either taxonomically or with regard to the biology of the component species. Apart from the very large number of fish species (estimated to be approximately 40 000), and the difficulties posed by the medium in which they live, there are other reasons for the above state of affairs. An obvious and universal reason is the shortage of funding available for taxonomic, biological and ecological studies, with increasing emphasis being placed on aquaculture, mariculture and fisheries related work. This situation is unlikely to improve and many research institutions around the world are operating on shrinking rather than expanding budgets. The onus of responsibility to disseminate information on the world’s fish faunas therefore rests squarely on the shoulders of those who are fortunate enough to be employed in the fascinating field of ichthyology. This book, which is a major revision and expansion of an earlier monograph (Whitfield 1998), is an attempt to synthesize the available information on fishes associated with southern African estuaries and to highlight the importance of conserving these systems for both fishes and people of the region. Limited reference is made to international estuarine fish research due to space constraints and readers are referred to global ichthyological reviews in this regard. The estuaries of southern Africa (defined as south of 26°S latitude for the purposes of this book) are highly diverse, both in terms of form and functioning. They range from the clear Kosi Estuary entering the coral rich subtropical Indian Ocean waters on the east coast, to the turbid Orange River flowing into the cool upwelled waters of the Atlantic Ocean on the west coast. The estuaries of the subcontinent are fed by catchments with a wide variety of climatic and geological characteristics. For example, the cool-temperate west coast is characterized by good winter rains and relatively dry summers, whereas on the subtropical east coast the opposite rainfall pattern prevails. While most south-western Cape estuaries are fed by rivers with low suspended sediment levels, those of KwaZulu-Natal normally carry high silt loads during the rainy season. Between Mossel Bay and St Francis Bay, rainfall patterns show no distinct seasonal peak and relatively acidic waters with low nutrient levels enter a variety of estuarine types along this section of the coast. The Eastern Cape is a region of transition between the subtropical and warm-temperate biogeographic provinces, and is prone to both droughts and floods occurring during any season of the year. The southern African estuarine environment is an unpredictable and often harsh habitat to occupy, yet each year millions of larval and juvenile fishes enter and thrive in these systems. The fish species that utilize estuaries as nursery areas exhibit great diversity in size, body form, salinity tolerance, diet, habitat preference and breeding behaviour. There is also a complete gradation in terms of the dependence that each species has on the estuarine environment. These and many other issues relating to the biology and ecology of estuary-associated fish species in southern Africa are explored in the chapters to follow. It is my sincere wish that our improved knowledge of these species and their environmental requirements will contribute to the wise management and conservation of these valuable ecosystems. , 2022 Edition
- Full Text:
- Date Issued: 2022
Framed African beadwork artefact
- Date: 2022 , 2022-10-11
- Subjects: Bam, Brigalia , Beadwork
- Language: English
- Type: realia
- Identifier: http://hdl.handle.net/10948/57165 , vital:57345
- Description: Framed African beadwork artefact. , Donated/gifted to Nelson Mandela University Archives , Forms part of: Brigalia Bam collection
- Full Text: false
- Date Issued: 2022
- Date: 2022 , 2022-10-11
- Subjects: Bam, Brigalia , Beadwork
- Language: English
- Type: realia
- Identifier: http://hdl.handle.net/10948/57165 , vital:57345
- Description: Framed African beadwork artefact. , Donated/gifted to Nelson Mandela University Archives , Forms part of: Brigalia Bam collection
- Full Text: false
- Date Issued: 2022