In vitro cytotoxic effects of chemical constituents of Euphorbia grandicornis Blanc against breast cancer cells
- Kemboi, Douglas, Peter, Xolani, Langat, Moses K, Mhlanga, Richwell, Vukea, Nyeleti, de la Mare, Jo-Anne, Siwe-Noundou, Xavier, Krause, Rui W M, Tembu, Vuyelwa J
- Authors: Kemboi, Douglas , Peter, Xolani , Langat, Moses K , Mhlanga, Richwell , Vukea, Nyeleti , de la Mare, Jo-Anne , Siwe-Noundou, Xavier , Krause, Rui W M , Tembu, Vuyelwa J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191747 , vital:45160 , xlink:href="https://doi.org/10.1016/j.sciaf.2021.e01002"
- Description: Euphorbia grandicornis Blanc is widely utilized in traditional medicine for a variety of ailments including body pains associated with skin irritations, inflammation, and snake or scorpion bites. Compounds from E. grandicornis were characterized using spectroscopic techniques, NMR, IR, MS, and melting points and alongside the extracts were evaluated for in vitro anticancer activity against several cancer cell lines. The root extract afforded known, β-glutinol (1), β-amyrin (2), 24-methylenetirucalla-8-en-3β-ol (3), tirucalla-8,25-diene-3β,24R-diol (4), stigmasterol (5), sitosterol (6), and hexyl (E)-3-(4-hydroxy-3-methoxyphenyl)-2-propenoate (7) based on their NMR spectroscopic data for the first report in E. grandicornis. The extracts and isolated compounds were evaluated for anticancer activities against hormone receptor-positive breast cancer (MCF-7), triple-negative breast cancer (HCC70), and non-tumorigenic mammary epithelial (MCF-12A) cell lines. The CH2Cl2 extract exhibited potent, cytotoxicity against MCF-7, HCC70, and MCF-12A cells. The aerial extract exhibited IC50 values of 1.03, 0.301, and 1.68 µg/mL, and root extract displayed IC50 values of 0.83, 0.83 and 3.98 µg/mL against MCF-7, HCC70, and MCF-12A cells respectively. The root extract thus showed selectivity for the cancer cell lines over the non-cancerous control cell line (SI = 4.80). Hexyl (E)-3-(4-hydroxy-3-methoxyphenyl)-2-propenoate (7) showed significant activity with IC50 values of 23.41, 29.45 and 27.01 µM against MCF-7, HCC70 and MCF-12A cells respectively, suggesting non-specific cytotoxicity.
- Full Text:
- Date Issued: 2021
- Authors: Kemboi, Douglas , Peter, Xolani , Langat, Moses K , Mhlanga, Richwell , Vukea, Nyeleti , de la Mare, Jo-Anne , Siwe-Noundou, Xavier , Krause, Rui W M , Tembu, Vuyelwa J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191747 , vital:45160 , xlink:href="https://doi.org/10.1016/j.sciaf.2021.e01002"
- Description: Euphorbia grandicornis Blanc is widely utilized in traditional medicine for a variety of ailments including body pains associated with skin irritations, inflammation, and snake or scorpion bites. Compounds from E. grandicornis were characterized using spectroscopic techniques, NMR, IR, MS, and melting points and alongside the extracts were evaluated for in vitro anticancer activity against several cancer cell lines. The root extract afforded known, β-glutinol (1), β-amyrin (2), 24-methylenetirucalla-8-en-3β-ol (3), tirucalla-8,25-diene-3β,24R-diol (4), stigmasterol (5), sitosterol (6), and hexyl (E)-3-(4-hydroxy-3-methoxyphenyl)-2-propenoate (7) based on their NMR spectroscopic data for the first report in E. grandicornis. The extracts and isolated compounds were evaluated for anticancer activities against hormone receptor-positive breast cancer (MCF-7), triple-negative breast cancer (HCC70), and non-tumorigenic mammary epithelial (MCF-12A) cell lines. The CH2Cl2 extract exhibited potent, cytotoxicity against MCF-7, HCC70, and MCF-12A cells. The aerial extract exhibited IC50 values of 1.03, 0.301, and 1.68 µg/mL, and root extract displayed IC50 values of 0.83, 0.83 and 3.98 µg/mL against MCF-7, HCC70, and MCF-12A cells respectively. The root extract thus showed selectivity for the cancer cell lines over the non-cancerous control cell line (SI = 4.80). Hexyl (E)-3-(4-hydroxy-3-methoxyphenyl)-2-propenoate (7) showed significant activity with IC50 values of 23.41, 29.45 and 27.01 µM against MCF-7, HCC70 and MCF-12A cells respectively, suggesting non-specific cytotoxicity.
- Full Text:
- Date Issued: 2021
Inclusion as social justice: Nancy Fraser’s theory in the South African context
- Musara, Ellison, Grant, Carolyn, Vorster, Jo-Anne E
- Authors: Musara, Ellison , Grant, Carolyn , Vorster, Jo-Anne E
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/453493 , vital:75258 , ISBN 978-3-030-35858-7 , https://doi.org/10.1007/978-3-030-35858-7_107
- Description: Current research suggests that the meaning of inclusion and social justice is still widely contested despite the seeming global acceptance of these educational reforms in most nations. While inclusion and social justice policies are now prevalent in many countries, these concepts bear discussion because they remain elusive and thus subject to numerous interpretations. This chapter reports on conceptualizations of inclusion and social justice in the South African context by authors who live and work in South Africa. They critically examine the concept of inclusion using American critical theorist-feminist Nancy Fraser’s social justice framework. The authors demonstrate how this substantive theory of justice usefully provides conceptual tools for understanding inequalities and inequities in education. An analysis is presented of inclusion as social justice and demonstrates what it looks like in the real-life practice of a South African case. Educators will find conceptual tools aimed at creating meaningful interventions in the areas of inclusion, equity, and social justice that support diverse learners with wide-ranging needs.
- Full Text:
- Date Issued: 2021
- Authors: Musara, Ellison , Grant, Carolyn , Vorster, Jo-Anne E
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/453493 , vital:75258 , ISBN 978-3-030-35858-7 , https://doi.org/10.1007/978-3-030-35858-7_107
- Description: Current research suggests that the meaning of inclusion and social justice is still widely contested despite the seeming global acceptance of these educational reforms in most nations. While inclusion and social justice policies are now prevalent in many countries, these concepts bear discussion because they remain elusive and thus subject to numerous interpretations. This chapter reports on conceptualizations of inclusion and social justice in the South African context by authors who live and work in South Africa. They critically examine the concept of inclusion using American critical theorist-feminist Nancy Fraser’s social justice framework. The authors demonstrate how this substantive theory of justice usefully provides conceptual tools for understanding inequalities and inequities in education. An analysis is presented of inclusion as social justice and demonstrates what it looks like in the real-life practice of a South African case. Educators will find conceptual tools aimed at creating meaningful interventions in the areas of inclusion, equity, and social justice that support diverse learners with wide-ranging needs.
- Full Text:
- Date Issued: 2021
Industry 4.0 and Skills Deficiencies in the HRM Function: Case Study of the HRM Department of a selected organisation in Cape Town
- Asoba, Samson Nambei, Patricia, Nteboheng Mefi
- Authors: Asoba, Samson Nambei , Patricia, Nteboheng Mefi
- Date: 2021
- Subjects: Personel Management Industry 4.0 Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/8095 , vital:61395 , xlink:href="https://www.abacademies.org/articles/industry-40-and-skills-deficiencies-in-the-hrm-function-case-study-of-the-hrm-department-of-a-selected-organization-in-cape-town-10664.html"
- Description: The study was formulated to tap into the future of HRM given the disruptions arising from the Covid-119 pandemic as well as the progression of the global technological environment to the fourth industrial revolution. The aim of the study was to: the Covid-19 induced HRM practices underpinning future organizational competitiveness. A literature review strategy was adopted to achieve the study objective. The study established seven emerging themes to inform HRM practices for the competitiveness of organizations in future following the Covid-19 disturbances. These themes are: primacy of HRM, increased cyber influences, digitalization, remote HRM, human-machine interface skills, human-organisation strategic links as well as human-technology interface competencies. Based on the study findings, the study recommended HRM departments to move to HR 4.0 through the adoption of industry 4.0 technologies, increased automation, and digitalization as well as strengthen virtualization systems.
- Full Text:
- Date Issued: 2021
- Authors: Asoba, Samson Nambei , Patricia, Nteboheng Mefi
- Date: 2021
- Subjects: Personel Management Industry 4.0 Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/8095 , vital:61395 , xlink:href="https://www.abacademies.org/articles/industry-40-and-skills-deficiencies-in-the-hrm-function-case-study-of-the-hrm-department-of-a-selected-organization-in-cape-town-10664.html"
- Description: The study was formulated to tap into the future of HRM given the disruptions arising from the Covid-119 pandemic as well as the progression of the global technological environment to the fourth industrial revolution. The aim of the study was to: the Covid-19 induced HRM practices underpinning future organizational competitiveness. A literature review strategy was adopted to achieve the study objective. The study established seven emerging themes to inform HRM practices for the competitiveness of organizations in future following the Covid-19 disturbances. These themes are: primacy of HRM, increased cyber influences, digitalization, remote HRM, human-machine interface skills, human-organisation strategic links as well as human-technology interface competencies. Based on the study findings, the study recommended HRM departments to move to HR 4.0 through the adoption of industry 4.0 technologies, increased automation, and digitalization as well as strengthen virtualization systems.
- Full Text:
- Date Issued: 2021
Infant health: a community-based assessment and educational intervention in two rural communities in the Eastern Cape.
- Authors: Kuzeeko, Faith
- Date: 2021
- Subjects: Angus Gillis Foundation (South Africa) , Infants -- Mortality -- South Africa , Infants -- Health and hygiene -- South Africa , Breastfeeding -- South Africa -- Eastern Cape , Infants -- Care -- Equipment and supplies , Infants -- Care -- South Africa -- Eastern Cape -- Case studies , Children -- Mortality -- South Africa , High throughput screening (Drug development)
- Language: English
- Type: text , Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/170837 , vital:41964
- Description: South Africa is on track to attaining the 2030 Agenda on reducing under-five deaths to 25 deaths per 1000 live births at its current momentum, however an unacceptable amount of infants are still at risk from preventable illnesses. Malnutrition is the major underlined cause of infant mortality rates in South Africa. Exclusive breastfeeding rates are low nationwide due to low exposure to breastfeeding information, some mothers having other commitments and others having breastfeeding difficulties. Implementation and expansion of simple, cost-effective interventions, such as exclusive breastfeeding for six months to reduce and/or prevent infant mortality rates, remains low in South Africa. The aim of the study was to determine one infant health issue of major concern to participants in two rural villages in the Eastern Cape, namely Glenmore and Ndwayana. The identified infant health issue was used to design an educational intervention in the villages. This was the second phase of this study. A community-based participatory approach was utilized in which the Angus Gillis Foundation, a non-profit organization that works in these communities, was one of the stakeholders. Stock status of WHO priority medicines for infants, semi-structured interviews and focus group discussions were carried out during the baseline study. The intervention phase contained pre-2 intervention semi-structured interviews with ten pregnant women followed by an educational intervention with nine out of the ten; and finally, a post-intervention with seven out of the ten women. A questionnaire was completed by members of the Angus Gillis Foundation to provide feedback on the sustainability of the intervention. Semi-structured interviews revealed that medicines stocked at the clinic parallel those indicated in the WHO priority medicines list for infants. The results from the focus group discussions indicated that mothers do not exclusively breastfeed their infants during the first six months. Pre- and post-intervention results on exclusive breastfeeding illustrated a positive change in participants’ knowledge and intent to breastfeed exclusively for six months. They showed a better understanding of the importance of exclusive breastfeeding and indicated a more focussed intention and confidence to carry out optimal breastfeeding practices. In the questionnaire the members of the Angus Gillis Foundation stated that the intervention is sustainable as it was linked with the existing networks. These include educational programs carried out in the villages by the foundation together with positive health champions, community health workers and women self-help groups; which will be able to build on the present knowledge base. Finally, the study also included the design of a booklet on the identified infant health issue. In conclusion, participants highlighted lack of understanding regarding breastfeeding as an issue of concern during the baseline phase of the study. This community-based educational intervention improved the understanding of breastfeeding among the participants, resulting in a positive change in perception with regards to exclusive breastfeeding practices.
- Full Text:
- Date Issued: 2021
- Authors: Kuzeeko, Faith
- Date: 2021
- Subjects: Angus Gillis Foundation (South Africa) , Infants -- Mortality -- South Africa , Infants -- Health and hygiene -- South Africa , Breastfeeding -- South Africa -- Eastern Cape , Infants -- Care -- Equipment and supplies , Infants -- Care -- South Africa -- Eastern Cape -- Case studies , Children -- Mortality -- South Africa , High throughput screening (Drug development)
- Language: English
- Type: text , Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/170837 , vital:41964
- Description: South Africa is on track to attaining the 2030 Agenda on reducing under-five deaths to 25 deaths per 1000 live births at its current momentum, however an unacceptable amount of infants are still at risk from preventable illnesses. Malnutrition is the major underlined cause of infant mortality rates in South Africa. Exclusive breastfeeding rates are low nationwide due to low exposure to breastfeeding information, some mothers having other commitments and others having breastfeeding difficulties. Implementation and expansion of simple, cost-effective interventions, such as exclusive breastfeeding for six months to reduce and/or prevent infant mortality rates, remains low in South Africa. The aim of the study was to determine one infant health issue of major concern to participants in two rural villages in the Eastern Cape, namely Glenmore and Ndwayana. The identified infant health issue was used to design an educational intervention in the villages. This was the second phase of this study. A community-based participatory approach was utilized in which the Angus Gillis Foundation, a non-profit organization that works in these communities, was one of the stakeholders. Stock status of WHO priority medicines for infants, semi-structured interviews and focus group discussions were carried out during the baseline study. The intervention phase contained pre-2 intervention semi-structured interviews with ten pregnant women followed by an educational intervention with nine out of the ten; and finally, a post-intervention with seven out of the ten women. A questionnaire was completed by members of the Angus Gillis Foundation to provide feedback on the sustainability of the intervention. Semi-structured interviews revealed that medicines stocked at the clinic parallel those indicated in the WHO priority medicines list for infants. The results from the focus group discussions indicated that mothers do not exclusively breastfeed their infants during the first six months. Pre- and post-intervention results on exclusive breastfeeding illustrated a positive change in participants’ knowledge and intent to breastfeed exclusively for six months. They showed a better understanding of the importance of exclusive breastfeeding and indicated a more focussed intention and confidence to carry out optimal breastfeeding practices. In the questionnaire the members of the Angus Gillis Foundation stated that the intervention is sustainable as it was linked with the existing networks. These include educational programs carried out in the villages by the foundation together with positive health champions, community health workers and women self-help groups; which will be able to build on the present knowledge base. Finally, the study also included the design of a booklet on the identified infant health issue. In conclusion, participants highlighted lack of understanding regarding breastfeeding as an issue of concern during the baseline phase of the study. This community-based educational intervention improved the understanding of breastfeeding among the participants, resulting in a positive change in perception with regards to exclusive breastfeeding practices.
- Full Text:
- Date Issued: 2021
Institutionalised business incubation: a frontier for accelerating entrepreneurship in African countries
- Authors: Lose, Thobekani
- Date: 2021
- Subjects: Economic indicators , Economic growth , Business incubators
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7405 , vital:53977 , https://www.abacademies.org/articles/institutionalised-business-incubation-a-frontier-for-accelerating-entrepreneurship-in-african-countries-9989.html
- Description: Africa is a growing hub for small, medium and large enterprise. This paper attempts to cement the need to create business incubation institutions in South Africa (as well as in other African countries) so as to promote a superior entrepreneurial ecosystem for economic growth. The Africa of tomorrow needs solutions that last and one key component is the progress of entrepreneurship as an employment strategy, an innovation and creativity platform, and a key economic factor. This study employs a narrative overview of literature to explore an institutionalised business incubation concept as a frontier for accelerating entrepreneurship in African countries. The study found that the need for institutionalised business incubation has become pervasive for superior entrepreneurial ecosystems across economies. The study recommends that central governments need to promote the development of local, regional and national institutions for the strong development of incubation as well as entrepreneurship.
- Full Text:
- Date Issued: 2021
- Authors: Lose, Thobekani
- Date: 2021
- Subjects: Economic indicators , Economic growth , Business incubators
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7405 , vital:53977 , https://www.abacademies.org/articles/institutionalised-business-incubation-a-frontier-for-accelerating-entrepreneurship-in-african-countries-9989.html
- Description: Africa is a growing hub for small, medium and large enterprise. This paper attempts to cement the need to create business incubation institutions in South Africa (as well as in other African countries) so as to promote a superior entrepreneurial ecosystem for economic growth. The Africa of tomorrow needs solutions that last and one key component is the progress of entrepreneurship as an employment strategy, an innovation and creativity platform, and a key economic factor. This study employs a narrative overview of literature to explore an institutionalised business incubation concept as a frontier for accelerating entrepreneurship in African countries. The study found that the need for institutionalised business incubation has become pervasive for superior entrepreneurial ecosystems across economies. The study recommends that central governments need to promote the development of local, regional and national institutions for the strong development of incubation as well as entrepreneurship.
- Full Text:
- Date Issued: 2021
Interaction of silver nanoparticles with catechol O-methyltransferase: Spectroscopic and simulation analyses
- Usman, Aminu, Lobb, Kevin A, Pletschke, Brett I, Whiteley, Christopher G, Wilhelmi, Brendan S
- Authors: Usman, Aminu , Lobb, Kevin A , Pletschke, Brett I , Whiteley, Christopher G , Wilhelmi, Brendan S
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451095 , vital:75018 , xlink:href=" https://doi.org/10.1016/j.bbrep.2021.101013"
- Description: Catechol O-methyltransferase, an enzyme involved in the metabolism of catechol containing compounds, catalyzes the transfer of a methyl group between S-adenosylmethionine and the hydroxyl groups of the catechol. Furthermore it is considered a potential drug target for Parkinson’s disease as it metabolizes the drug levodopa. Consequently inhibitors of the enzyme would increase levels of levodopa. In this study, absorption, fluorescence and infrared spectroscopy as well as computational simulation studies investigated human soluble catechol Omethyltransferase interaction with silver nanoparticles. The nanoparticles form a corona with the enzyme and quenches the fluorescence of Trp143. This amino acid maintains the correct structural orientation for the catechol ring during catalysis through a static mechanism supported by a non-fluorescent fluorophore–nanoparticle complex. The enzyme has one binding site for AgNPs in a thermodynamically spontaneous binding driven by electrostatic interactions as confirmed by negative ΔG and ΔH and positive ΔS values. Fourier transform infrared spectroscopy within the amide I region of the enzyme indicated that the interaction causes relaxation of its β− structures, while simulation studies indicated the involvement of six polar amino acids. These findings suggest AgNPs influence the catalytic activity of catechol O-methyltransferase, and therefore have potential in controlling the activity of the enzyme.
- Full Text:
- Date Issued: 2021
- Authors: Usman, Aminu , Lobb, Kevin A , Pletschke, Brett I , Whiteley, Christopher G , Wilhelmi, Brendan S
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451095 , vital:75018 , xlink:href=" https://doi.org/10.1016/j.bbrep.2021.101013"
- Description: Catechol O-methyltransferase, an enzyme involved in the metabolism of catechol containing compounds, catalyzes the transfer of a methyl group between S-adenosylmethionine and the hydroxyl groups of the catechol. Furthermore it is considered a potential drug target for Parkinson’s disease as it metabolizes the drug levodopa. Consequently inhibitors of the enzyme would increase levels of levodopa. In this study, absorption, fluorescence and infrared spectroscopy as well as computational simulation studies investigated human soluble catechol Omethyltransferase interaction with silver nanoparticles. The nanoparticles form a corona with the enzyme and quenches the fluorescence of Trp143. This amino acid maintains the correct structural orientation for the catechol ring during catalysis through a static mechanism supported by a non-fluorescent fluorophore–nanoparticle complex. The enzyme has one binding site for AgNPs in a thermodynamically spontaneous binding driven by electrostatic interactions as confirmed by negative ΔG and ΔH and positive ΔS values. Fourier transform infrared spectroscopy within the amide I region of the enzyme indicated that the interaction causes relaxation of its β− structures, while simulation studies indicated the involvement of six polar amino acids. These findings suggest AgNPs influence the catalytic activity of catechol O-methyltransferase, and therefore have potential in controlling the activity of the enzyme.
- Full Text:
- Date Issued: 2021
Interviews and surveys
- Shackleton, Sheona E, Bezerra, Joana C, Cockburn, Jessica J, Reed, Maureen G, Abu, Razak
- Authors: Shackleton, Sheona E , Bezerra, Joana C , Cockburn, Jessica J , Reed, Maureen G , Abu, Razak
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433914 , vital:73009 , ISBN 9781000401516 , https://library.oapen.org/handle/20.500.12657/49560
- Description: This chapter is closely related to the following approaches and methods in this handbook: systems scoping (Chapter 5), participatory data collection (Chapter 8), facilitated dialogues (Chapter 9), futures analysis (Chapter 10), qualitative content analysis (Chapter 19), comparative case study analysis (Chapter 20), institutional analysis (Chapter 22), network analysis (Chapter 23), spatial mapping and analysis (Chapter 24), historical assessment (Chapter 25), and livelihood and vulnerability analysis (Chapter 32).
- Full Text:
- Date Issued: 2021
- Authors: Shackleton, Sheona E , Bezerra, Joana C , Cockburn, Jessica J , Reed, Maureen G , Abu, Razak
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433914 , vital:73009 , ISBN 9781000401516 , https://library.oapen.org/handle/20.500.12657/49560
- Description: This chapter is closely related to the following approaches and methods in this handbook: systems scoping (Chapter 5), participatory data collection (Chapter 8), facilitated dialogues (Chapter 9), futures analysis (Chapter 10), qualitative content analysis (Chapter 19), comparative case study analysis (Chapter 20), institutional analysis (Chapter 22), network analysis (Chapter 23), spatial mapping and analysis (Chapter 24), historical assessment (Chapter 25), and livelihood and vulnerability analysis (Chapter 32).
- Full Text:
- Date Issued: 2021
Introducing DerivatizeME and its Application in the Augmentation of a Natural Product Library
- Sigauke, Lester T, Taştan Bishop, Özlem, Lobb, Kevin A
- Authors: Sigauke, Lester T , Taştan Bishop, Özlem , Lobb, Kevin A
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451120 , vital:75020 , xlink:href="https://doi.org/10.1142/S2737416521500101"
- Description: The large chemical space universe can be traversed by screening libraries of compounds that possess novel medicinally relevant chemistries, properties and complexity criteria. These libraries can be populated with the use of exhaustive, de novo approaches or inspired, combinatorial approaches. By assuming that natural products within screening libraries may be classified as a source of feedstock for populating virtual libraries, they can act as scaffolds upon which exhaustive approaches may be used in exploring chemical space. In order to achieve this, we have built DerivatizeME as a tool that enumerates derivatives of query compounds in order to evaluate their relevance for further assessment and development. This technique was applied to natural products present in the South African natural compound database (SANCDB). By expanding the chemical space of SANCDB compounds through the generation of SANCDB derivatives, we were able to graduate some natural products that were in undesirable regions of medicinally relevant chemical space, to acceptable regions of this chemical space. These modified scaffolds are available for further development, testing and evaluation in a manner similar to natural product driven focused libraries. The natural product parent is used, through its derivatives, instead of being discarded from screening protocols. This approach has the potential to enhance the efficiency of the natural product library in providing successful hits, amplifying the potential that they possess to access both novel bioactives and privileged scaffolds which may have otherwise been overlooked.
- Full Text:
- Date Issued: 2021
- Authors: Sigauke, Lester T , Taştan Bishop, Özlem , Lobb, Kevin A
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451120 , vital:75020 , xlink:href="https://doi.org/10.1142/S2737416521500101"
- Description: The large chemical space universe can be traversed by screening libraries of compounds that possess novel medicinally relevant chemistries, properties and complexity criteria. These libraries can be populated with the use of exhaustive, de novo approaches or inspired, combinatorial approaches. By assuming that natural products within screening libraries may be classified as a source of feedstock for populating virtual libraries, they can act as scaffolds upon which exhaustive approaches may be used in exploring chemical space. In order to achieve this, we have built DerivatizeME as a tool that enumerates derivatives of query compounds in order to evaluate their relevance for further assessment and development. This technique was applied to natural products present in the South African natural compound database (SANCDB). By expanding the chemical space of SANCDB compounds through the generation of SANCDB derivatives, we were able to graduate some natural products that were in undesirable regions of medicinally relevant chemical space, to acceptable regions of this chemical space. These modified scaffolds are available for further development, testing and evaluation in a manner similar to natural product driven focused libraries. The natural product parent is used, through its derivatives, instead of being discarded from screening protocols. This approach has the potential to enhance the efficiency of the natural product library in providing successful hits, amplifying the potential that they possess to access both novel bioactives and privileged scaffolds which may have otherwise been overlooked.
- Full Text:
- Date Issued: 2021
Investigating grade R teacher institutional identity presented in policy and expressed through narrative in a time of transition
- Authors: Long, Roxanne
- Date: 2021
- Subjects: Early childhood education -- South Africa , Early childhood education -- Government policy -- South Africa , Child development -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/171346 , vital:42051 , 10.21504/10962/171346
- Description: This study investigated Grade R (reception year) teacher institutional identity presented in policy and expressed through teacher narratives. The study was conducted in the context of a major national policy transition that involved the physical and contextual shift of Grade R out of the Early Childhood Development sector and into the formal schooling sector. This study highlighted the way in which this shift has resulted in mixed policy messages, which have implications for Grade R teachers’ institutional identities and learning trajectories across their landscapes of practice. The thesis begins by exploring the South African Education context in general as well as the Early Childhood Development context in particular. In order to understand the institutional identities of Grade R teachers as both storied by others (in policy) and by themselves, the study conducted a documentary analysis of policy relating to Grade R teachers and Grade R teacher narrative expressions of their identities. The methodological approach of the study involved a qualitative approach, drawing on grounded theory analytical techniques to closely examine policy documents and teacher generated data gathered through interviews and questionnaires. The study was guided by a sociocultural perspective and drew on three key sociocultural theorists whose work provided complementary perspectives on teacher identity. Sfard and Prusak’s (2005) operationalization of identity as narratives was used to define the unit of analysis for the study (i.e. identities as stories). Gee’s (2000) definition and conceptualization of institutional identity was supplemented with Wenger-Trayner, Fenton-O'Creevy, Hutchinson, Kubiak, and Wenger-Trayner’s (2015) notion of identity as journeying across landscapes of practice. This complementary framing allowed for focused and detailed analysis of policy documents and Grade R teacher identity stories. The study addresses the research gap of an under-representation of identity research in early childhood teacher education and particularly in the South African context. This study is significant as it is the first study of its kind to explore the importance of identity formation for Grade R teachers as newcomers to the formal schooling landscape. Findings from the policy analysis point to mixed messages moving across a spectrum of descriptors from the not yet qualified ‘mothers and ‘caregivers’ to qualified ‘specialised’ educators. These descriptors have implications for the differentiated roles and responsibilities (institutional identity) of Grade R teachers. The findings from teacher identity narratives highlighted tension in the navigation of the policy promoted institutional identities. Teacher narratives pointed to vastly contrasting experiences of teachers with specialised and qualified institutional teacher identities to those with not yet qualified institutional identities. For the former, there were high levels of confidence in their job security and in terms of recognition received from others. For the latter, however, there was vulnerability in terms of the stability of their jobs and remuneration as well as low levels of recognition from others. The study draws on the findings from the analysis to suggest recommendations for Grade R policy, Grade R teacher education (both inservice and pre-service); as well as Grade R professional development initiatives.
- Full Text:
- Date Issued: 2021
- Authors: Long, Roxanne
- Date: 2021
- Subjects: Early childhood education -- South Africa , Early childhood education -- Government policy -- South Africa , Child development -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/171346 , vital:42051 , 10.21504/10962/171346
- Description: This study investigated Grade R (reception year) teacher institutional identity presented in policy and expressed through teacher narratives. The study was conducted in the context of a major national policy transition that involved the physical and contextual shift of Grade R out of the Early Childhood Development sector and into the formal schooling sector. This study highlighted the way in which this shift has resulted in mixed policy messages, which have implications for Grade R teachers’ institutional identities and learning trajectories across their landscapes of practice. The thesis begins by exploring the South African Education context in general as well as the Early Childhood Development context in particular. In order to understand the institutional identities of Grade R teachers as both storied by others (in policy) and by themselves, the study conducted a documentary analysis of policy relating to Grade R teachers and Grade R teacher narrative expressions of their identities. The methodological approach of the study involved a qualitative approach, drawing on grounded theory analytical techniques to closely examine policy documents and teacher generated data gathered through interviews and questionnaires. The study was guided by a sociocultural perspective and drew on three key sociocultural theorists whose work provided complementary perspectives on teacher identity. Sfard and Prusak’s (2005) operationalization of identity as narratives was used to define the unit of analysis for the study (i.e. identities as stories). Gee’s (2000) definition and conceptualization of institutional identity was supplemented with Wenger-Trayner, Fenton-O'Creevy, Hutchinson, Kubiak, and Wenger-Trayner’s (2015) notion of identity as journeying across landscapes of practice. This complementary framing allowed for focused and detailed analysis of policy documents and Grade R teacher identity stories. The study addresses the research gap of an under-representation of identity research in early childhood teacher education and particularly in the South African context. This study is significant as it is the first study of its kind to explore the importance of identity formation for Grade R teachers as newcomers to the formal schooling landscape. Findings from the policy analysis point to mixed messages moving across a spectrum of descriptors from the not yet qualified ‘mothers and ‘caregivers’ to qualified ‘specialised’ educators. These descriptors have implications for the differentiated roles and responsibilities (institutional identity) of Grade R teachers. The findings from teacher identity narratives highlighted tension in the navigation of the policy promoted institutional identities. Teacher narratives pointed to vastly contrasting experiences of teachers with specialised and qualified institutional teacher identities to those with not yet qualified institutional identities. For the former, there were high levels of confidence in their job security and in terms of recognition received from others. For the latter, however, there was vulnerability in terms of the stability of their jobs and remuneration as well as low levels of recognition from others. The study draws on the findings from the analysis to suggest recommendations for Grade R policy, Grade R teacher education (both inservice and pre-service); as well as Grade R professional development initiatives.
- Full Text:
- Date Issued: 2021
Investigating popular CNN architectures for plant disease detection
- Poole, Louise C, Brown, Dane L
- Authors: Poole, Louise C , Brown, Dane L
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/465168 , vital:76579 , xlink:href="https://ieeexplore.ieee.org/abstract/document/9519341"
- Description: Food production and food security have become increasingly important due to climate change and rising population numbers. One method to prevent crop loss is to develop a system to allow for early, efficient and accurate identification of plant diseases. CNNs often outperform previously popular machine learning algorithms. There are many existing CNN architectures. We compared and analysed the popular state-of-the-art architectures, namely ResNet, GoogLeNet and VGG, when trained for plant disease classification. We found that ResNet performed the best on the balanced Mendeley Leaves and PlantVillage datasets, obtaining 91.95% and 95.80% accuracy respectively. However, the ResNet architecture was relatively computationally expensive and slow to train. GoogLeNet obtained accuracies very close to those of ResNet with 89.35% and 94.59% achieved on the Mendeley Leaves and PlantVillage datasets respectively and could be considered a less computationally expensive alternative.
- Full Text:
- Date Issued: 2021
- Authors: Poole, Louise C , Brown, Dane L
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/465168 , vital:76579 , xlink:href="https://ieeexplore.ieee.org/abstract/document/9519341"
- Description: Food production and food security have become increasingly important due to climate change and rising population numbers. One method to prevent crop loss is to develop a system to allow for early, efficient and accurate identification of plant diseases. CNNs often outperform previously popular machine learning algorithms. There are many existing CNN architectures. We compared and analysed the popular state-of-the-art architectures, namely ResNet, GoogLeNet and VGG, when trained for plant disease classification. We found that ResNet performed the best on the balanced Mendeley Leaves and PlantVillage datasets, obtaining 91.95% and 95.80% accuracy respectively. However, the ResNet architecture was relatively computationally expensive and slow to train. GoogLeNet obtained accuracies very close to those of ResNet with 89.35% and 94.59% achieved on the Mendeley Leaves and PlantVillage datasets respectively and could be considered a less computationally expensive alternative.
- Full Text:
- Date Issued: 2021
Investigating the Nature of Biodiversity Knowledge in Natural Sciences Curriculum and Textbooks
- Mmekwa, Makwena, Schudel, Ingrid J
- Authors: Mmekwa, Makwena , Schudel, Ingrid J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435060 , vital:73127 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: In 1992, the international Convention on Biological Diversity (CBD) emphasised biodiversity as a measure for sustainabil-ity and recognised communication, education and public awareness as important for the successful implementation of the Convention’s aims (CBD 1992). In 2002, the United Na-tions Decade of Education for Sustainable Development (2005–2014) included biodiversity as one of its key priorities (Unesco 2005). Later, Unesco’s (2014) Global Action Plan on Education for Sustainable Development highlighted biodiver-sity as ‘critical content’, to be included in national curricula for holistic and transformational education. In 2015, the United Nations included a concern for biodiversity in the Sustainable Development Goals, making a commitment that: We recog-nise that social and economic development depends on the sustainable management of our planet’s natural resources. We are therefore determined to conserve and sustainably use oceans and seas, freshwater resources, as well as for-ests, mountains and dry lands and to protect biodiversity, ecosystems and wildlife. (United Nations 2015: 13).
- Full Text:
- Date Issued: 2021
- Authors: Mmekwa, Makwena , Schudel, Ingrid J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435060 , vital:73127 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: In 1992, the international Convention on Biological Diversity (CBD) emphasised biodiversity as a measure for sustainabil-ity and recognised communication, education and public awareness as important for the successful implementation of the Convention’s aims (CBD 1992). In 2002, the United Na-tions Decade of Education for Sustainable Development (2005–2014) included biodiversity as one of its key priorities (Unesco 2005). Later, Unesco’s (2014) Global Action Plan on Education for Sustainable Development highlighted biodiver-sity as ‘critical content’, to be included in national curricula for holistic and transformational education. In 2015, the United Nations included a concern for biodiversity in the Sustainable Development Goals, making a commitment that: We recog-nise that social and economic development depends on the sustainable management of our planet’s natural resources. We are therefore determined to conserve and sustainably use oceans and seas, freshwater resources, as well as for-ests, mountains and dry lands and to protect biodiversity, ecosystems and wildlife. (United Nations 2015: 13).
- Full Text:
- Date Issued: 2021
Iris colour changes and behaviour in the Three-streaked Tchagra Tchagra jamesi: an observation from the past
- Authors: Craig, Adrian J F K
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449851 , vital:74857 , https://www.ajol.info/index.php/scopus/article/view/211291
- Description: The African bush-shrikes (Malaconotidae) are one of the bird families in which a significant number of species have a distinctively coloured iris (Craig and Hulley 2004). However, in this review paper we overlooked both the description of the Threestreaked Tchagra Tchagra jamesi in two standard handbooks (Archer and Godman 1961, Pearson 2000), and some published observations by a well-known East African ornithologist, VGL van Someren. Changes in pupil size, or in iris coloration, seem to be close-range signals which are not often obvious to a human spectator—they are presumably directed at conspecific birds who are likely to be less than 1 m away. Some instances have thus been reported by bird-ringers with the bird in the hand (eg, Black-bellied Starling Notopholia corusca, McCulloch 1963, Britton and Britton 1970). However, keen observers and especially photographers may be alert to such subtle changes in appearance.
- Full Text:
- Date Issued: 2021
- Authors: Craig, Adrian J F K
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449851 , vital:74857 , https://www.ajol.info/index.php/scopus/article/view/211291
- Description: The African bush-shrikes (Malaconotidae) are one of the bird families in which a significant number of species have a distinctively coloured iris (Craig and Hulley 2004). However, in this review paper we overlooked both the description of the Threestreaked Tchagra Tchagra jamesi in two standard handbooks (Archer and Godman 1961, Pearson 2000), and some published observations by a well-known East African ornithologist, VGL van Someren. Changes in pupil size, or in iris coloration, seem to be close-range signals which are not often obvious to a human spectator—they are presumably directed at conspecific birds who are likely to be less than 1 m away. Some instances have thus been reported by bird-ringers with the bird in the hand (eg, Black-bellied Starling Notopholia corusca, McCulloch 1963, Britton and Britton 1970). However, keen observers and especially photographers may be alert to such subtle changes in appearance.
- Full Text:
- Date Issued: 2021
Knowledge of formal and informal regulations affecting wild plant foraging practices in urban spaces in South Africa
- Garekae, Hesekia, Shackleton, Charlie M
- Authors: Garekae, Hesekia , Shackleton, Charlie M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/403221 , vital:69935 , xlink:href="https://doi.org/10.1016/j.forpol.2021.102659"
- Description: Although foraging wild plants is commonly perceived to be synonymous with rural areas, it is now increasingly recognized in urban areas. Notwithstanding, the regulations conditioning access to and rights to foraging in urban green spaces have seldom been examined. This study explored the formal and informal regulations governing access to and defining rights to forageable plant resources in the towns of Potchefstroom and Thabazimbi, South Africa. A random sample of 374 households was considered for the survey, complemented by in-depth interviews with 26 participants. Foraging occurred in a variety of public and private spaces, with the frequency of access differing with the type of space. The majority of the respondents were unaware of formal and informal regulations governing access to and use of urban landscapes. Recognizing foraging activities in urban landscapes is a fundamental step toward fostering active community involvement in the management and production of urban green spaces.
- Full Text:
- Date Issued: 2021
- Authors: Garekae, Hesekia , Shackleton, Charlie M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/403221 , vital:69935 , xlink:href="https://doi.org/10.1016/j.forpol.2021.102659"
- Description: Although foraging wild plants is commonly perceived to be synonymous with rural areas, it is now increasingly recognized in urban areas. Notwithstanding, the regulations conditioning access to and rights to foraging in urban green spaces have seldom been examined. This study explored the formal and informal regulations governing access to and defining rights to forageable plant resources in the towns of Potchefstroom and Thabazimbi, South Africa. A random sample of 374 households was considered for the survey, complemented by in-depth interviews with 26 participants. Foraging occurred in a variety of public and private spaces, with the frequency of access differing with the type of space. The majority of the respondents were unaware of formal and informal regulations governing access to and use of urban landscapes. Recognizing foraging activities in urban landscapes is a fundamental step toward fostering active community involvement in the management and production of urban green spaces.
- Full Text:
- Date Issued: 2021
Kuntanshi yamikalile (The Future): speculative nonconformity in the works of Zambian visual artists
- Authors: Mulenga, Andrew Mukuka
- Date: 2021
- Subjects: Future in art , Africa -- In art , Art, Zambian , Art, African , Artists -- Zambia , Nyandoro, Gareth
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172203 , vital:42175 , 10.21504/10962/172203
- Description: In recent years, select African visual artists practising on the continent as well as in its diaspora have increasingly been attracted to themes that explore, portray or grapple with Africa’s future. Along with this increasing popularity of the ‘future’ or indeed ‘African futuristic’ themes by visual artists, such themes have also attracted academic consideration among various scholars, resulting primarily in topics described as ‘African Futurism’ or Afrofuturism. These are topics that may be used to disrupt what some scholars – across disciplines and in various contexts – have highlighted as the persistent presumptive notions that portray Africa as a hinterland (Hassan 1999; Sefa Dei, Hall and Goldin Rosenberg 2000; Simbao 2007; Soyinka-Airewele and Edozie 2010; Moyo 2013; Keita, L. 2014; Green 2014; Serpell 2016). This study makes an effort to critique certain aspects of ‘African Art History’ with regard to the representation of Africa, and raises the following question: How can an analysis of artistic portrayals of ‘the future’ portrayed in the works of select contemporary Zambian artists be used to critique the positioning of Africa as ‘backward’, an occurrence at the intersection of a dualistic framing of tradition versus modern. Furthermore, how can this be used to break down this dichotomy in order to challenge lingering perceptions of African belatedness? The study analyses ways in which this belatedness is challenged by the juxtaposition of traditional, contemporary and futuristic elements by discussing a series of topics and debates associated to African cultures and technology that may be deemed disconnected from the contemporary lived experiences of Africans based on the continent. The study acknowledges that there is no singular ‘African Art History’ that one can talk of and there have been various shifts in how it has been perceived. I argue that while currently the African art history that is written in the West does not simplistically position Africa as backward as it may have done in the past, there appear to be moments of a hangover of this perception (Lamp 1999:4). What started out as a largely Western scholarly discourse of African art history occurred in about the 1950s and the journal African Arts started in the 1960s. Even before contemporary African art became a big thing in the 1990s for the largely US- and Europe-based discourses there were many discussions in the US about how the ‘old’ art history tended to freeze time and that this was not appropriate (Drewal 1991 et al). In order to advance the discourse on contemporary African visual arts I present critical analyses of the select works of Zambian artists to develop interpretations of the broader uses of the aforementioned themes. The evidence that supports the core argument of this research is embedded in the images discussed throughout this dissertation. The artists featured in the study span several decades including artists who were active from the 1960s to the 1980s, such as Henry Tayali and Akwila Simpasa, as well as artists who have been practising since the 1980s, such as Chishimba Chansa and William Miko and those that are more current and have been producing work from the early 1990s and 2000s, such as Zenzele Chulu, Milumbe Haimbe, Stary Mwaba, Isaac Kalambata and Roy Jethro Phiri.
- Full Text:
- Date Issued: 2021
- Authors: Mulenga, Andrew Mukuka
- Date: 2021
- Subjects: Future in art , Africa -- In art , Art, Zambian , Art, African , Artists -- Zambia , Nyandoro, Gareth
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172203 , vital:42175 , 10.21504/10962/172203
- Description: In recent years, select African visual artists practising on the continent as well as in its diaspora have increasingly been attracted to themes that explore, portray or grapple with Africa’s future. Along with this increasing popularity of the ‘future’ or indeed ‘African futuristic’ themes by visual artists, such themes have also attracted academic consideration among various scholars, resulting primarily in topics described as ‘African Futurism’ or Afrofuturism. These are topics that may be used to disrupt what some scholars – across disciplines and in various contexts – have highlighted as the persistent presumptive notions that portray Africa as a hinterland (Hassan 1999; Sefa Dei, Hall and Goldin Rosenberg 2000; Simbao 2007; Soyinka-Airewele and Edozie 2010; Moyo 2013; Keita, L. 2014; Green 2014; Serpell 2016). This study makes an effort to critique certain aspects of ‘African Art History’ with regard to the representation of Africa, and raises the following question: How can an analysis of artistic portrayals of ‘the future’ portrayed in the works of select contemporary Zambian artists be used to critique the positioning of Africa as ‘backward’, an occurrence at the intersection of a dualistic framing of tradition versus modern. Furthermore, how can this be used to break down this dichotomy in order to challenge lingering perceptions of African belatedness? The study analyses ways in which this belatedness is challenged by the juxtaposition of traditional, contemporary and futuristic elements by discussing a series of topics and debates associated to African cultures and technology that may be deemed disconnected from the contemporary lived experiences of Africans based on the continent. The study acknowledges that there is no singular ‘African Art History’ that one can talk of and there have been various shifts in how it has been perceived. I argue that while currently the African art history that is written in the West does not simplistically position Africa as backward as it may have done in the past, there appear to be moments of a hangover of this perception (Lamp 1999:4). What started out as a largely Western scholarly discourse of African art history occurred in about the 1950s and the journal African Arts started in the 1960s. Even before contemporary African art became a big thing in the 1990s for the largely US- and Europe-based discourses there were many discussions in the US about how the ‘old’ art history tended to freeze time and that this was not appropriate (Drewal 1991 et al). In order to advance the discourse on contemporary African visual arts I present critical analyses of the select works of Zambian artists to develop interpretations of the broader uses of the aforementioned themes. The evidence that supports the core argument of this research is embedded in the images discussed throughout this dissertation. The artists featured in the study span several decades including artists who were active from the 1960s to the 1980s, such as Henry Tayali and Akwila Simpasa, as well as artists who have been practising since the 1980s, such as Chishimba Chansa and William Miko and those that are more current and have been producing work from the early 1990s and 2000s, such as Zenzele Chulu, Milumbe Haimbe, Stary Mwaba, Isaac Kalambata and Roy Jethro Phiri.
- Full Text:
- Date Issued: 2021
Leadership Styles and Employee Job Satisfaction: A Case of Head of Departments in Walter Sisulu UniversityMonitoring and Management Mechanisms on Stress in HEI in Eastern Cape Province in South Africa: Critical Review
- Asoba, Samson Nambei, Patricia, Nteboheng Mefi
- Authors: Asoba, Samson Nambei , Patricia, Nteboheng Mefi
- Date: 2021
- Subjects: Educational Leadership Education (Higher) College department heads Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/8082 , vital:61392 , xlink:href="https://www.abacademies.org/articles/leadership-styles-and-employee-job-satisfaction-a-case-of-head-of-departments-in-walter-sisulu-university-10942.html"
- Description: This study was based on the relationship between the leadership styles of Academic head of Department and employee job satisfaction at the Higher Education Institution (HEI). In so doing, the study was based on the following questions: What is the relationship between leadership styles of HODs and employee job satisfaction in a Higher Education institution in the Eastern Cape Province of South Africa. A purposive sampling technique was utilised to select the participants, which comprised 80 academic staff members to which the researcher hand-delivered 80 questionnaires. The study employed a quantitative method to collect and analyse data. The study found that Perceptions on the leadership styles of academic HODs at the HEI are varied. No clear pattern emerged on what leadership styles are prevalent. The relationship between leadership styles and employee job satisfaction appears to be nonlinear. Job satisfaction is a phenomenon that is determined by many factors, not simply leadership styles.
- Full Text:
- Date Issued: 2021
- Authors: Asoba, Samson Nambei , Patricia, Nteboheng Mefi
- Date: 2021
- Subjects: Educational Leadership Education (Higher) College department heads Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/8082 , vital:61392 , xlink:href="https://www.abacademies.org/articles/leadership-styles-and-employee-job-satisfaction-a-case-of-head-of-departments-in-walter-sisulu-university-10942.html"
- Description: This study was based on the relationship between the leadership styles of Academic head of Department and employee job satisfaction at the Higher Education Institution (HEI). In so doing, the study was based on the following questions: What is the relationship between leadership styles of HODs and employee job satisfaction in a Higher Education institution in the Eastern Cape Province of South Africa. A purposive sampling technique was utilised to select the participants, which comprised 80 academic staff members to which the researcher hand-delivered 80 questionnaires. The study employed a quantitative method to collect and analyse data. The study found that Perceptions on the leadership styles of academic HODs at the HEI are varied. No clear pattern emerged on what leadership styles are prevalent. The relationship between leadership styles and employee job satisfaction appears to be nonlinear. Job satisfaction is a phenomenon that is determined by many factors, not simply leadership styles.
- Full Text:
- Date Issued: 2021
Lipid nanocarriers : a novel approach to delivering ophthalmic clarithromycin
- Authors: Makoni, Pedzisai Anotida
- Date: 2021
- Subjects: Clarithromycin , Nanomedicine , Nanostructures , Antibiotics , Eye -- Diseases -- Treatment , Ocular pharmacology , Ophthalmic drugs , Karatitis -- Chemotherapy
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/171678 , vital:42109 , 10.21504/10962/171678
- Description: The feasibility of incorporating clarithromycin (CLA) into innovative solid lipid nanoparticles (SLN) and nanostructured lipi d carriers (NLC) using hot emulsification ultrasonication (HEUS) was investigated. This approach was investigated in an attempt to address the shortcomings associated with the use of lyophilized parenteral formulations administered via the ocular route suc h as toxic reactions, intolerance and patient discomfort due to frequent insti llation of topical solutions of CLA. In particular, sustained release approaches to delivery may enhance precorneal retention, increase ocular availability and permit dose reduction or use of a longer dosing frequency when treating ocular non - tuberculous m ycobacterial (NTM) keratitis infections. This approach may potentially improve the delivery of CLA to the eye, thereby addressing some or all of the unmet clinical needs described vide infra . Prior to initiating pre - formulation, formulation development a nd optimization studies of CLA - loaded SLN and/or NLC, Design of Experiments (DoE), specifically a Central Composite Design (CCD) was used in conjunction with Response Surface Methodology (RSM) to develop and optimize a suitable method for the quantitative determination of CLA in pharmaceutical formulations and for monitoring CLA release from SLN and/or NLC in vitro . A simple, accurate, precise, sensitive and stability - indicating reversed phase - high performance liquid chromatography (RP - HPLC) method with ele ctrochemical (EC) detection was developed, validated and optimized for the in vitro analysis of CLA loaded SLN and/or NLC formulations. Pre - formulation studies were undertaken to investigate the thermal stability of CLA and bulk lipids to facilitate the s election of lipid excipients for the manufacture of nanocarriers in addition to establishing compatibility of CLA with the excipients. It was established that CLA was thermostable up to a temperature of approximately 300 °C thereby indicating that HEUS cou ld be used for the manufacture of CLA - loaded SLN and/or NLC. Lipid screening revealed that CLA i s, in general, poorly soluble in solid and liquid lipids however a combination of stearic acid (SA) and Transcutol ® HP (THP) exhibited the best dissolution pote ntial for CLA of all lipids tested . Stearic acid appears to exist as polymorphic form B prior to exposure to heat however occurs as the form C polymorph following heating at 85 °C for one hour. The best ratio for the mixture of SA and THP for the manufactu re of CLA - NLC ii was an 80:20 ( w/w ) ratio of SA: THP as the two lipids are miscible in this ratio and exhibited the greatest dissolution potential for CLA. Furthermore, an investigation of binary mixtures of CLA/SA and SA/Transcutol ® HP, in addition to eutect ic mixtures of CLA, SA and Transcutol ® HP, revealed no obvious interaction between CLA and the lipids selected for the production of the nanocarriers. Due to the relatively high solubility of CLA in THP in comparison to SA, NLC are likely to exhibit a hig her loading capacity (LC) and encapsulation efficiency (EE) for CLA than SLN. Consequently the feasibility of incorporating CLA (10% w/w ) into NLC was investigated and evaluation of the production of SLN was not undertaken as the production of these might not result in the manufacture of a delivery technology with a high EE and LC for CLA. Tween ® 20 was used as the surfactant as it is readily available, exhibits little or no cytotoxicity and is relatively cheap. Polyethylene glycol (PEG) was used as a coati ng polymer to impart muco - adhesive properties the formulated CLA - NLC. Response surface methodology (RSM) in conjunction with DoE, specifically a Box - Behnken Design (BBD) used as a screening design was used to identify a formulation composition which would produce a product that would meet the pre - defined target critical quality attributes (CQA) for the nanoparticles viz. particle size (PS) in the nano - range, polydispersity index (PDI) < 0.5, Zeta Potential (ZP) ≥ ± 30 mV, and EE > 80%. The formulation composition identified was subsequently used for the optimization of the manufacturing parameters viz. sonication time and amplitude, using a Central Composite Design (CCD) . The LC and EE, in vitro CLA release, cytotoxicity, osmolarity, pH, degree of crystallinity and lipid modification, elemental analysis and surface morphology of the optimized batch was investigated and mon itored to ensure that CLA - loaded NLC, of the desirable quality, had been produced. On the day of manufacture the mean PS and PDI of the optimized CLA - loaded NLC formulation adjusted to physiological osmolarity (250 – 450 mOsm/kg) was 461.9 ± 40.16 nm and 0. 523 ± 0.104, respectively. The ZP for the optimized NLC generated on the day of manufacture using HPLC grade water as the dispersion medium was - 20.5 ± 4.82 mV. The pH and osmolarity of the optimized CLA - loaded NLC formulation was 7.76 ± 0.01 and 316 ± iii 2 m Osm/Kg, respectively and the EE was 88.62 ± 0.23 %. The optimized NLC exhibited a decreased crystallinity in comparison to the bulk lipid materials. DSC, WAXS and FT - IR revealed that CLA was molecularly dispersed in the nanocarriers. The optimized CLA - load ed NLC exhibited muco - adhesive properties, when tested under stationary conditions using laser doppler anemometry (LDA). The optimized formulation also exhibited sustained release of CLA over 24 hours during in vitro release testing and CLA release was bes t described using the Baker - Lonsdale model . The cumulative % CLA released over 24 hours was 56.13 ± 0.23% and mass balance analysis revealed 41.38 ± 0.02% CLA had been retained in the NLC. In vitro cytotoxicity testing revealed that the optimized CLA - NLC w ere less cytotoxic to HeLa cells when compared to CLA alone and further confirmed that the lipids and excipients used in these studies were of GRAS status . Stability studies revealed that the EE reduced over 28 days by 14.42% and 5.14% when stored at 4 °C and 22 °C , respectively. In addition, the particle size increased from the nm to μm range for samples stored at 22 °C. The findings are a good starting point but require further optimization to ensure prolongation of stability. In addition , the technology requires additional developmental studies and a powder for reconstitution for use as a single - dose considered as single dose packaging may be a solution to the compromised formulation stability observed in these studies. The CLA - NLC produced in these stu dies exhibit sound product attributes which serve as a useful foundation for the novel delivery of antibiotics to the eye. The results suggest that the optimized NLC have the potential to enhance precorneal retention and increase ocular availability of CLA , which in turn may be useful to reduce the required dose and dosing frequency when administering CLA as a reconstituted solution to treat susceptible organisms that infect ocular tissues.
- Full Text:
- Date Issued: 2021
- Authors: Makoni, Pedzisai Anotida
- Date: 2021
- Subjects: Clarithromycin , Nanomedicine , Nanostructures , Antibiotics , Eye -- Diseases -- Treatment , Ocular pharmacology , Ophthalmic drugs , Karatitis -- Chemotherapy
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/171678 , vital:42109 , 10.21504/10962/171678
- Description: The feasibility of incorporating clarithromycin (CLA) into innovative solid lipid nanoparticles (SLN) and nanostructured lipi d carriers (NLC) using hot emulsification ultrasonication (HEUS) was investigated. This approach was investigated in an attempt to address the shortcomings associated with the use of lyophilized parenteral formulations administered via the ocular route suc h as toxic reactions, intolerance and patient discomfort due to frequent insti llation of topical solutions of CLA. In particular, sustained release approaches to delivery may enhance precorneal retention, increase ocular availability and permit dose reduction or use of a longer dosing frequency when treating ocular non - tuberculous m ycobacterial (NTM) keratitis infections. This approach may potentially improve the delivery of CLA to the eye, thereby addressing some or all of the unmet clinical needs described vide infra . Prior to initiating pre - formulation, formulation development a nd optimization studies of CLA - loaded SLN and/or NLC, Design of Experiments (DoE), specifically a Central Composite Design (CCD) was used in conjunction with Response Surface Methodology (RSM) to develop and optimize a suitable method for the quantitative determination of CLA in pharmaceutical formulations and for monitoring CLA release from SLN and/or NLC in vitro . A simple, accurate, precise, sensitive and stability - indicating reversed phase - high performance liquid chromatography (RP - HPLC) method with ele ctrochemical (EC) detection was developed, validated and optimized for the in vitro analysis of CLA loaded SLN and/or NLC formulations. Pre - formulation studies were undertaken to investigate the thermal stability of CLA and bulk lipids to facilitate the s election of lipid excipients for the manufacture of nanocarriers in addition to establishing compatibility of CLA with the excipients. It was established that CLA was thermostable up to a temperature of approximately 300 °C thereby indicating that HEUS cou ld be used for the manufacture of CLA - loaded SLN and/or NLC. Lipid screening revealed that CLA i s, in general, poorly soluble in solid and liquid lipids however a combination of stearic acid (SA) and Transcutol ® HP (THP) exhibited the best dissolution pote ntial for CLA of all lipids tested . Stearic acid appears to exist as polymorphic form B prior to exposure to heat however occurs as the form C polymorph following heating at 85 °C for one hour. The best ratio for the mixture of SA and THP for the manufactu re of CLA - NLC ii was an 80:20 ( w/w ) ratio of SA: THP as the two lipids are miscible in this ratio and exhibited the greatest dissolution potential for CLA. Furthermore, an investigation of binary mixtures of CLA/SA and SA/Transcutol ® HP, in addition to eutect ic mixtures of CLA, SA and Transcutol ® HP, revealed no obvious interaction between CLA and the lipids selected for the production of the nanocarriers. Due to the relatively high solubility of CLA in THP in comparison to SA, NLC are likely to exhibit a hig her loading capacity (LC) and encapsulation efficiency (EE) for CLA than SLN. Consequently the feasibility of incorporating CLA (10% w/w ) into NLC was investigated and evaluation of the production of SLN was not undertaken as the production of these might not result in the manufacture of a delivery technology with a high EE and LC for CLA. Tween ® 20 was used as the surfactant as it is readily available, exhibits little or no cytotoxicity and is relatively cheap. Polyethylene glycol (PEG) was used as a coati ng polymer to impart muco - adhesive properties the formulated CLA - NLC. Response surface methodology (RSM) in conjunction with DoE, specifically a Box - Behnken Design (BBD) used as a screening design was used to identify a formulation composition which would produce a product that would meet the pre - defined target critical quality attributes (CQA) for the nanoparticles viz. particle size (PS) in the nano - range, polydispersity index (PDI) < 0.5, Zeta Potential (ZP) ≥ ± 30 mV, and EE > 80%. The formulation composition identified was subsequently used for the optimization of the manufacturing parameters viz. sonication time and amplitude, using a Central Composite Design (CCD) . The LC and EE, in vitro CLA release, cytotoxicity, osmolarity, pH, degree of crystallinity and lipid modification, elemental analysis and surface morphology of the optimized batch was investigated and mon itored to ensure that CLA - loaded NLC, of the desirable quality, had been produced. On the day of manufacture the mean PS and PDI of the optimized CLA - loaded NLC formulation adjusted to physiological osmolarity (250 – 450 mOsm/kg) was 461.9 ± 40.16 nm and 0. 523 ± 0.104, respectively. The ZP for the optimized NLC generated on the day of manufacture using HPLC grade water as the dispersion medium was - 20.5 ± 4.82 mV. The pH and osmolarity of the optimized CLA - loaded NLC formulation was 7.76 ± 0.01 and 316 ± iii 2 m Osm/Kg, respectively and the EE was 88.62 ± 0.23 %. The optimized NLC exhibited a decreased crystallinity in comparison to the bulk lipid materials. DSC, WAXS and FT - IR revealed that CLA was molecularly dispersed in the nanocarriers. The optimized CLA - load ed NLC exhibited muco - adhesive properties, when tested under stationary conditions using laser doppler anemometry (LDA). The optimized formulation also exhibited sustained release of CLA over 24 hours during in vitro release testing and CLA release was bes t described using the Baker - Lonsdale model . The cumulative % CLA released over 24 hours was 56.13 ± 0.23% and mass balance analysis revealed 41.38 ± 0.02% CLA had been retained in the NLC. In vitro cytotoxicity testing revealed that the optimized CLA - NLC w ere less cytotoxic to HeLa cells when compared to CLA alone and further confirmed that the lipids and excipients used in these studies were of GRAS status . Stability studies revealed that the EE reduced over 28 days by 14.42% and 5.14% when stored at 4 °C and 22 °C , respectively. In addition, the particle size increased from the nm to μm range for samples stored at 22 °C. The findings are a good starting point but require further optimization to ensure prolongation of stability. In addition , the technology requires additional developmental studies and a powder for reconstitution for use as a single - dose considered as single dose packaging may be a solution to the compromised formulation stability observed in these studies. The CLA - NLC produced in these stu dies exhibit sound product attributes which serve as a useful foundation for the novel delivery of antibiotics to the eye. The results suggest that the optimized NLC have the potential to enhance precorneal retention and increase ocular availability of CLA , which in turn may be useful to reduce the required dose and dosing frequency when administering CLA as a reconstituted solution to treat susceptible organisms that infect ocular tissues.
- Full Text:
- Date Issued: 2021
Livelihood and vulnerability analysis
- Shackleton, Charlie M, Schreckenberg, Kate, Shackleton, Sheona E, Luckert, Marty
- Authors: Shackleton, Charlie M , Schreckenberg, Kate , Shackleton, Sheona E , Luckert, Marty
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433811 , vital:73002 , ISBN 9781000401516 , https://library.oapen.org/handle/20.500.12657/49560
- Description: Livelihood analysis and vulnerability analysis are integrative approaches and consequently draw on a variety of methods to collect and analyse primary and secondary data covered in other chapters. Core ones include systems scoping (Chapter 5), ecological field data collection (Chapter 6), interviews and surveys (Chapter 7), participatory data collection (Chapter 8), action research (Chapter 15), statistical analysis (Chapter 18), qualitative content analysis (Chapter 19), comparative case study analysis (Chapter 20), institutional analysis (Chapter 22) and spatial mapping and analysis (Chapter 24).
- Full Text:
- Date Issued: 2021
- Authors: Shackleton, Charlie M , Schreckenberg, Kate , Shackleton, Sheona E , Luckert, Marty
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433811 , vital:73002 , ISBN 9781000401516 , https://library.oapen.org/handle/20.500.12657/49560
- Description: Livelihood analysis and vulnerability analysis are integrative approaches and consequently draw on a variety of methods to collect and analyse primary and secondary data covered in other chapters. Core ones include systems scoping (Chapter 5), ecological field data collection (Chapter 6), interviews and surveys (Chapter 7), participatory data collection (Chapter 8), action research (Chapter 15), statistical analysis (Chapter 18), qualitative content analysis (Chapter 19), comparative case study analysis (Chapter 20), institutional analysis (Chapter 22) and spatial mapping and analysis (Chapter 24).
- Full Text:
- Date Issued: 2021
Local use and knowledge of Hyphaene coriacea and Phoenix reclinata in Zitundo area, southern Mozambique:
- Martins, Angelina R O, Shackleton, Charlie M
- Authors: Martins, Angelina R O , Shackleton, Charlie M
- Date: 2021
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/175801 , vital:42625 , https://doi.org/10.1016/j.sajb.2020.12.011
- Description: Hyphaene coriacea and Phoenix reclinata are two abundant palm species in the Maputaland coastal plains of southern Mozambique. They provide an array of subsistence and commercial non- timber forest products. This research characterizes the ethnobotanical knowledge and uses of these species. Using structured interviews we assessed the knowledge, past and current uses, cultural importance and the determinants of the knowledge and current uses of these species. The knowledge about the uses of these two palms is widespread, however only 32% of respondents are engaged in palm exploitation. Thirteen palm products are used in the area with palm wine production from the sap of both species being the dominant activity, followed by broom production.
- Full Text:
- Date Issued: 2021
- Authors: Martins, Angelina R O , Shackleton, Charlie M
- Date: 2021
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/175801 , vital:42625 , https://doi.org/10.1016/j.sajb.2020.12.011
- Description: Hyphaene coriacea and Phoenix reclinata are two abundant palm species in the Maputaland coastal plains of southern Mozambique. They provide an array of subsistence and commercial non- timber forest products. This research characterizes the ethnobotanical knowledge and uses of these species. Using structured interviews we assessed the knowledge, past and current uses, cultural importance and the determinants of the knowledge and current uses of these species. The knowledge about the uses of these two palms is widespread, however only 32% of respondents are engaged in palm exploitation. Thirteen palm products are used in the area with palm wine production from the sap of both species being the dominant activity, followed by broom production.
- Full Text:
- Date Issued: 2021
Low‐temperature physiology of climatically distinct south African populations of the biological control agent Neochetina eichhorniae
- Rogers, Daniel J, Terblanche, John S, Owen, Candice A
- Authors: Rogers, Daniel J , Terblanche, John S , Owen, Candice A
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444421 , vital:74239 , https://doi.org/10.1111/een.12935
- Description: Neochetina eichhorniae is the most widely established biocontrol agent on water hyacinth populations around South Africa. However, some N. eichhorniae populations have failed to adequately control their host population, specifically those exposed to cold conditions. The aim of this study was to determine whether two climatically distinct populations of N. eichhorniae in South Africa differ in their low‐temperature physiol-ogy, which tests whether local-climate adaptation has occurred.
- Full Text:
- Date Issued: 2021
- Authors: Rogers, Daniel J , Terblanche, John S , Owen, Candice A
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444421 , vital:74239 , https://doi.org/10.1111/een.12935
- Description: Neochetina eichhorniae is the most widely established biocontrol agent on water hyacinth populations around South Africa. However, some N. eichhorniae populations have failed to adequately control their host population, specifically those exposed to cold conditions. The aim of this study was to determine whether two climatically distinct populations of N. eichhorniae in South Africa differ in their low‐temperature physiol-ogy, which tests whether local-climate adaptation has occurred.
- Full Text:
- Date Issued: 2021
Macrofauna associated with intertidal mussel beds in the Knysna estuarine embayment, South Africa
- Hodgson, Alan N, Smith, Frances, Smith, Peter, Claasens, Louw
- Authors: Hodgson, Alan N , Smith, Frances , Smith, Peter , Claasens, Louw
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443554 , vital:74131 , https://hdl.handle.net/10520/ejc-afzoo_v56_i1_a44
- Description: The alien invasive mussel, Mytilus galloprovincialis, forms biogenic habitats in the embayment of Knysna Estuary. Invertebrate macrofauna inhabiting mussel beds were sampled from six sites in the embayment. In addition, mussel cover, mussel bed depth, density and size of mussels were recorded. With the exception of two sites (The Heads and Featherbed) where some Perna perna was present, we confirmed that the mussel beds were composed of the invasive species M. galloprovincialis. At The Heads, mussel beds were single-layered and in patches, whereas at other sites they were multi-layered with 100% cover. Bed depth, mussel density and shell size varied among sites. A total of 65 taxa (mainly Crustacea and Mollusca) were identified across all sites with species richness and diversity being significantly different among sites. Forty-three percent of taxa were new records for the estuary. Macrofaunal richness and diversity were highest at the two sites (The Heads and Featherbed) closest to the mouth of the embayment. There were negative relationships between species diversity and mussel density, and diversity and macroinvertebrate abundance. At most sites macrofaunal abundance was dominated by one or two species. Multivariate analysis revealed a significant difference in species composition among sites. Where wave action was present (The Heads, Featherbed and Leisure Isle) only a few deposit feeders were present in the mussel beds. At sites where wave action was minimal (Thesen Wharf, Marina and Railway Bridge) fine silt was present in the mussel matrix and there was an increase in the number of deposit feeding species.
- Full Text:
- Date Issued: 2021
- Authors: Hodgson, Alan N , Smith, Frances , Smith, Peter , Claasens, Louw
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443554 , vital:74131 , https://hdl.handle.net/10520/ejc-afzoo_v56_i1_a44
- Description: The alien invasive mussel, Mytilus galloprovincialis, forms biogenic habitats in the embayment of Knysna Estuary. Invertebrate macrofauna inhabiting mussel beds were sampled from six sites in the embayment. In addition, mussel cover, mussel bed depth, density and size of mussels were recorded. With the exception of two sites (The Heads and Featherbed) where some Perna perna was present, we confirmed that the mussel beds were composed of the invasive species M. galloprovincialis. At The Heads, mussel beds were single-layered and in patches, whereas at other sites they were multi-layered with 100% cover. Bed depth, mussel density and shell size varied among sites. A total of 65 taxa (mainly Crustacea and Mollusca) were identified across all sites with species richness and diversity being significantly different among sites. Forty-three percent of taxa were new records for the estuary. Macrofaunal richness and diversity were highest at the two sites (The Heads and Featherbed) closest to the mouth of the embayment. There were negative relationships between species diversity and mussel density, and diversity and macroinvertebrate abundance. At most sites macrofaunal abundance was dominated by one or two species. Multivariate analysis revealed a significant difference in species composition among sites. Where wave action was present (The Heads, Featherbed and Leisure Isle) only a few deposit feeders were present in the mussel beds. At sites where wave action was minimal (Thesen Wharf, Marina and Railway Bridge) fine silt was present in the mussel matrix and there was an increase in the number of deposit feeding species.
- Full Text:
- Date Issued: 2021