Electronic and nonlinear optical properties of 3-(((2-substituted-4-nitrophenyl) imino) methyl) phenol
- Ojo, Nathanael D, Krause, Rui W M, Obi-Egbedi, Nelson O
- Authors: Ojo, Nathanael D , Krause, Rui W M , Obi-Egbedi, Nelson O
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193408 , vital:45329 , xlink:href="https://doi.org/10.1016/j.comptc.2020.113050"
- Description: This work entails the study of electronic and nonlinear optical (NLO) properties of two synthesized Schiff bases namely 3-(((2-methyl-4-nitrophenyl)imino)methyl)phenol (MMP) and 3-(((2,4-dinitrophenyl)imino)methyl)phenol (DMP). Electronic absorption properties studied using UV–Visible spectrophotometry in ethanol reveal low-energy absorption indicating a low band gap. Time-dependent density functional calculations on their excited state properties with ωB97X-D/6-311++G(d,p) method show comparable transition energies and intensities with the experimental results. Energy gaps (ΔE) and NLO properties were evaluated from the frontier orbitals and hyperpolarizabilities (βtot and γ) in gas, cyclohexane and ethanol. Low ΔE obtained shows the potentials of the systems as organic semiconductor with remarkable band gap stabilization in ethanol. Higher βtot and γ than urea imply that the Schiff bases possess potentials for NLO applications. The solvatochromic shift in transition energies and perturbation of electronic properties reveal the solvent dependence of the electronic and optical properties of MMP and DMP due to solute-solvent interactions.
- Full Text:
- Date Issued: 2020
- Authors: Ojo, Nathanael D , Krause, Rui W M , Obi-Egbedi, Nelson O
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193408 , vital:45329 , xlink:href="https://doi.org/10.1016/j.comptc.2020.113050"
- Description: This work entails the study of electronic and nonlinear optical (NLO) properties of two synthesized Schiff bases namely 3-(((2-methyl-4-nitrophenyl)imino)methyl)phenol (MMP) and 3-(((2,4-dinitrophenyl)imino)methyl)phenol (DMP). Electronic absorption properties studied using UV–Visible spectrophotometry in ethanol reveal low-energy absorption indicating a low band gap. Time-dependent density functional calculations on their excited state properties with ωB97X-D/6-311++G(d,p) method show comparable transition energies and intensities with the experimental results. Energy gaps (ΔE) and NLO properties were evaluated from the frontier orbitals and hyperpolarizabilities (βtot and γ) in gas, cyclohexane and ethanol. Low ΔE obtained shows the potentials of the systems as organic semiconductor with remarkable band gap stabilization in ethanol. Higher βtot and γ than urea imply that the Schiff bases possess potentials for NLO applications. The solvatochromic shift in transition energies and perturbation of electronic properties reveal the solvent dependence of the electronic and optical properties of MMP and DMP due to solute-solvent interactions.
- Full Text:
- Date Issued: 2020
Encapsulation and physicochemical evaluation of efavirenz in liposomes
- Okafor, Nnamdi Ikemefuna, Nkanga, Christian I, Walker, Roderick B, Noundou, Xavier S, Krause, Rui W M
- Authors: Okafor, Nnamdi Ikemefuna , Nkanga, Christian I , Walker, Roderick B , Noundou, Xavier S , Krause, Rui W M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183414 , vital:43988 , xlink:href="https://doi.org/10.1007/s40005-019-00458-8"
- Description: Antiretroviral therapy remains the most efective means of managing the human immune defciency virus/acquired immune defciency syndrome (HIV/AIDS). Application of therapeutics has been hampered by factors including poor bioavailability of most anti-retroviral compounds (ARV), side efects and an alarming emergence of drug resistant strains of the virus. Recent developments and use of drug delivery systems (DDS) has shown potential for improving the pharmacological profle of ARV. Amongst these complex DDS, liposomes have been explored for delivery of ARV. In this study, we have aimed at exploring efcient encapsulation of efavirenz (EFV), a potent ARV using diferent mass ratios of crude soybean lecithin and cholesterol. The EFV-loaded liposomes (EFL) were prepared using thin flm hydration and evaluated for particle size, zeta potential (ZP), encapsulation efciency (EE%), morphology and drug release studies. Diferential scanning calorimetry (DSC), X-ray difraction (XRD), energy dispersity spectroscopy (EDS) and Fourier transform infrared (FTIR) spectroscopy were used for comprehensive physicochemical characterization of EFL. EFL exhibited high encapsulation (99%) in 1:1 crude lecithin to cholesterol mass ratio. The average particle size and Zeta Potential of EFL were found to be 411.10±7.40 nm and −53.5.3±0.06 mV, respectively. EFL showed a relatively controlled EFV release behaviour that was similar to the dissolution profle of un-encapsulated EFV. This suggests that EFL represents a promising vehicle for efective EFV delivery while providing the advantages of a nano-scaled delivery system
- Full Text:
- Date Issued: 2020
- Authors: Okafor, Nnamdi Ikemefuna , Nkanga, Christian I , Walker, Roderick B , Noundou, Xavier S , Krause, Rui W M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183414 , vital:43988 , xlink:href="https://doi.org/10.1007/s40005-019-00458-8"
- Description: Antiretroviral therapy remains the most efective means of managing the human immune defciency virus/acquired immune defciency syndrome (HIV/AIDS). Application of therapeutics has been hampered by factors including poor bioavailability of most anti-retroviral compounds (ARV), side efects and an alarming emergence of drug resistant strains of the virus. Recent developments and use of drug delivery systems (DDS) has shown potential for improving the pharmacological profle of ARV. Amongst these complex DDS, liposomes have been explored for delivery of ARV. In this study, we have aimed at exploring efcient encapsulation of efavirenz (EFV), a potent ARV using diferent mass ratios of crude soybean lecithin and cholesterol. The EFV-loaded liposomes (EFL) were prepared using thin flm hydration and evaluated for particle size, zeta potential (ZP), encapsulation efciency (EE%), morphology and drug release studies. Diferential scanning calorimetry (DSC), X-ray difraction (XRD), energy dispersity spectroscopy (EDS) and Fourier transform infrared (FTIR) spectroscopy were used for comprehensive physicochemical characterization of EFL. EFL exhibited high encapsulation (99%) in 1:1 crude lecithin to cholesterol mass ratio. The average particle size and Zeta Potential of EFL were found to be 411.10±7.40 nm and −53.5.3±0.06 mV, respectively. EFL showed a relatively controlled EFV release behaviour that was similar to the dissolution profle of un-encapsulated EFV. This suggests that EFL represents a promising vehicle for efective EFV delivery while providing the advantages of a nano-scaled delivery system
- Full Text:
- Date Issued: 2020
Enhanced Light-Driven Antimicrobial Activity of Cationic Poly (oxanorbornene) s by Phthalocyanine Incorporation into Polymer as Pendants
- Ahmetali, Erem, Sen, Pinar, Süer, N Ceren, Aksu, Burak, Nyokong, Tebello, Eren, Tarik, Sener, Kasim M
- Authors: Ahmetali, Erem , Sen, Pinar , Süer, N Ceren , Aksu, Burak , Nyokong, Tebello , Eren, Tarik , Sener, Kasim M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185976 , vital:44453 , xlink:href=" https://doi.org/10.1002/macp.202000386"
- Description: Amphiphilic poly(oxanorbornene)s are promising synthetic polymers that mimic the structural properties and antimicrobial functions of naturally occurring antimicrobial peptides. Here, poly(oxanorbornene)s bearing pendant zinc(II) phthalocyanine and triphenyl(ethyl) phosphonium functionalities are synthesized by ring-opening metathesis polymerization (ROMP). Fluorescence, singlet oxygen and triplet quantum yields of polymers are measured in dimethyl sulfoxide and aqueous medium. The singlet oxygen quantum yields of copolymers with the highest triphenyl and triethyl phosphonium content are found to be 0.29 and 0.41, respectively. Then, antimicrobial activities of polymers against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) are investigated under both dark and light conditions. Synergistic effect of zinc(II) phthalocyanine and phosphonium-containing poly(oxanorbornene) is observed that the conjugate possessing the most triphenyl phosphonium side chains has the highest activity under light against both gram-positive and gram-negative bacterial strains after 80 min irradiation, reducing the survival of E. coli or S. aureus by 99.9999%. Hemolytic concentrations of the copolymers are found between 8 and 512 µg mL−1. Scanning electron microscopy (SEM) proves that the bacteria membrane deforms after contacting with the biocidal polymer.
- Full Text:
- Date Issued: 2020
- Authors: Ahmetali, Erem , Sen, Pinar , Süer, N Ceren , Aksu, Burak , Nyokong, Tebello , Eren, Tarik , Sener, Kasim M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185976 , vital:44453 , xlink:href=" https://doi.org/10.1002/macp.202000386"
- Description: Amphiphilic poly(oxanorbornene)s are promising synthetic polymers that mimic the structural properties and antimicrobial functions of naturally occurring antimicrobial peptides. Here, poly(oxanorbornene)s bearing pendant zinc(II) phthalocyanine and triphenyl(ethyl) phosphonium functionalities are synthesized by ring-opening metathesis polymerization (ROMP). Fluorescence, singlet oxygen and triplet quantum yields of polymers are measured in dimethyl sulfoxide and aqueous medium. The singlet oxygen quantum yields of copolymers with the highest triphenyl and triethyl phosphonium content are found to be 0.29 and 0.41, respectively. Then, antimicrobial activities of polymers against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) are investigated under both dark and light conditions. Synergistic effect of zinc(II) phthalocyanine and phosphonium-containing poly(oxanorbornene) is observed that the conjugate possessing the most triphenyl phosphonium side chains has the highest activity under light against both gram-positive and gram-negative bacterial strains after 80 min irradiation, reducing the survival of E. coli or S. aureus by 99.9999%. Hemolytic concentrations of the copolymers are found between 8 and 512 µg mL−1. Scanning electron microscopy (SEM) proves that the bacteria membrane deforms after contacting with the biocidal polymer.
- Full Text:
- Date Issued: 2020
Enhanced photodynamic antimicrobial activity of surface modified SiNPs doped with zinc (II) phthalocyanines: The effect of antimicrobial ampicillin and extra charges from a sultone
- Magadla, Aviwe, Nyokong, Tebello
- Authors: Magadla, Aviwe , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186034 , vital:44457 , xlink:href="https://doi.org/10.1016/j.pdpdt.2020.101996"
- Description: 1-(2-Methoxyethyl) piperidine sustituted Zn phthalocyanine complex (2) is synthesised and quartenised (3). These complexes are loaded into silica nanoparticles (SiNPs) that are futher surface modified with ampicillin and 1.3-propanesultone. The photophysical and photochemical properties of the complexes and their doped conjugates were investigated in dimethylsulfoxide. The cationic complex (3) is used for photodynamic antimicrobial activity. Log reduction values of above 9 are obtained towards the photoiactivation of Staphyloccocus aureus.
- Full Text:
- Date Issued: 2020
- Authors: Magadla, Aviwe , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186034 , vital:44457 , xlink:href="https://doi.org/10.1016/j.pdpdt.2020.101996"
- Description: 1-(2-Methoxyethyl) piperidine sustituted Zn phthalocyanine complex (2) is synthesised and quartenised (3). These complexes are loaded into silica nanoparticles (SiNPs) that are futher surface modified with ampicillin and 1.3-propanesultone. The photophysical and photochemical properties of the complexes and their doped conjugates were investigated in dimethylsulfoxide. The cationic complex (3) is used for photodynamic antimicrobial activity. Log reduction values of above 9 are obtained towards the photoiactivation of Staphyloccocus aureus.
- Full Text:
- Date Issued: 2020
Enhancement of photodynamic antimicrobialtherapy through the use of cationic indium porphyrin conjugated to Ag/CuFe2O4 nanoparticles
- Makola, Collen L, Managa, Muthumuni, Nyokong, Tebello
- Authors: Makola, Collen L , Managa, Muthumuni , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186233 , vital:44475 , xlink:href="https://doi.org/10.1016/j.pdpdt.2020.101736"
- Description: Photodynamic antimicrobial chemotherapy (PACT) is being actively researched as a possible alternative for antimicrobial agents. This study focuses on the application of neutral indium 5-p-carboxyphenyl-10-15-20-(tri-4-pyridyl)porphyrin and cationic indium 5-p-carboxyphenyl-10-15-20-(tris-4-methylpyridyl)-porphyrin triiodide conjugated to 6-mercapo-1-hexanol functionalized Ag/CuFe2O4 magnetic nanoparticles for photo-inactivation of S. aureus bacteria. Comparative studies were done on quaternized and unquaternized indium porphyrin complexes conjugated to Ag/CuFe2O4, where log reduction of 9.27 was obtained for quaternized conjugate and 0.83 for unquaternized conjugate.
- Full Text:
- Date Issued: 2020
- Authors: Makola, Collen L , Managa, Muthumuni , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186233 , vital:44475 , xlink:href="https://doi.org/10.1016/j.pdpdt.2020.101736"
- Description: Photodynamic antimicrobial chemotherapy (PACT) is being actively researched as a possible alternative for antimicrobial agents. This study focuses on the application of neutral indium 5-p-carboxyphenyl-10-15-20-(tri-4-pyridyl)porphyrin and cationic indium 5-p-carboxyphenyl-10-15-20-(tris-4-methylpyridyl)-porphyrin triiodide conjugated to 6-mercapo-1-hexanol functionalized Ag/CuFe2O4 magnetic nanoparticles for photo-inactivation of S. aureus bacteria. Comparative studies were done on quaternized and unquaternized indium porphyrin complexes conjugated to Ag/CuFe2O4, where log reduction of 9.27 was obtained for quaternized conjugate and 0.83 for unquaternized conjugate.
- Full Text:
- Date Issued: 2020
Environmental health promotion at a National Science Festival: An experiential-education based approach
- Duxbury, Theodore, Bradshaw, Karen L, Khamanga, Sandile, Tandlich, Roman, Srinivas, Sunitha
- Authors: Duxbury, Theodore , Bradshaw, Karen L , Khamanga, Sandile , Tandlich, Roman , Srinivas, Sunitha
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440274 , vital:73762 , xlink:href="https://doi.org/10.1080/1533015X.2019.1567406"
- Description: To increase individual and communal environmental health awareness through an experiential-education project. A computer-based pre- and postintervention quiz; an educational poster; an interactive board game; and a take-home information leaflet were utilized for a school learners-centered health promotion exhibit at a National Science Festival in Grahamstown, South Africa. Out of all the participants, 55.7% were female, and 76.5% attended or had attended a government school. Participants showed significant improvement in their pre- and post educational intervention. The exhibit was effective in educating participants on environmental health, natural resources, and the impact environmental pollution has on their quality of life.
- Full Text:
- Date Issued: 2020
- Authors: Duxbury, Theodore , Bradshaw, Karen L , Khamanga, Sandile , Tandlich, Roman , Srinivas, Sunitha
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440274 , vital:73762 , xlink:href="https://doi.org/10.1080/1533015X.2019.1567406"
- Description: To increase individual and communal environmental health awareness through an experiential-education project. A computer-based pre- and postintervention quiz; an educational poster; an interactive board game; and a take-home information leaflet were utilized for a school learners-centered health promotion exhibit at a National Science Festival in Grahamstown, South Africa. Out of all the participants, 55.7% were female, and 76.5% attended or had attended a government school. Participants showed significant improvement in their pre- and post educational intervention. The exhibit was effective in educating participants on environmental health, natural resources, and the impact environmental pollution has on their quality of life.
- Full Text:
- Date Issued: 2020
Epistemic Cartography: Evaluating Net-Map as a Frontline Tool for Navigating Informal Knowledge Networks
- Meterlerkamp, Luke, Schiffer, Eva
- Authors: Meterlerkamp, Luke , Schiffer, Eva
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/388009 , vital:68298 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/188690"
- Description: Sustainability transitions are dependent on the development and diffusion of transformative skills and competencies. However, the prevailing notion that learning for sustainability transitions will be led by universities, technical colleges and other similar institutions is practically not feasible in much of the global south. Net-Map is a social network analysis tool that uses interviews and mapping to help people understand, visualise, discuss, and improve situations in which many different actors influence outcomes (Schiffer and Hauck, 2010). In response to the pressing need for new approaches to the development and diffusion of sustainability skills, this paper evaluates Net-Map’s suitability as a methodological tool for educators, knowledge brokers and students seeking to enhance the navigability of the often complex and uncharted occupational pathways they encounter. To do this, the research applied Net-Map to an emerging sustainability niche within the food system in order to map the learning pathways of successful sustainability pioneers. We found that Net-Map was helpful in identifying diffuse informal knowledge networks and teaching resources. Being free, quick to learn and easy to use, Net-Map is a potentially low-cost method for circumventing traditionally costly approaches to curriculum development and accreditation – assisting community-based actors to make sense of the informal knowledge and competency networks that support emerging career fields. In emerging career fields such as organic farming, where pioneer knowledge is fragmented, poorly documented and often disregarded by mainstream-science, Net-Map could be useful in the preparatory phase of curriculum planning and design, providing training designers, course conveners and facilitators with contextually informed insights.
- Full Text:
- Date Issued: 2020
- Authors: Meterlerkamp, Luke , Schiffer, Eva
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/388009 , vital:68298 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/188690"
- Description: Sustainability transitions are dependent on the development and diffusion of transformative skills and competencies. However, the prevailing notion that learning for sustainability transitions will be led by universities, technical colleges and other similar institutions is practically not feasible in much of the global south. Net-Map is a social network analysis tool that uses interviews and mapping to help people understand, visualise, discuss, and improve situations in which many different actors influence outcomes (Schiffer and Hauck, 2010). In response to the pressing need for new approaches to the development and diffusion of sustainability skills, this paper evaluates Net-Map’s suitability as a methodological tool for educators, knowledge brokers and students seeking to enhance the navigability of the often complex and uncharted occupational pathways they encounter. To do this, the research applied Net-Map to an emerging sustainability niche within the food system in order to map the learning pathways of successful sustainability pioneers. We found that Net-Map was helpful in identifying diffuse informal knowledge networks and teaching resources. Being free, quick to learn and easy to use, Net-Map is a potentially low-cost method for circumventing traditionally costly approaches to curriculum development and accreditation – assisting community-based actors to make sense of the informal knowledge and competency networks that support emerging career fields. In emerging career fields such as organic farming, where pioneer knowledge is fragmented, poorly documented and often disregarded by mainstream-science, Net-Map could be useful in the preparatory phase of curriculum planning and design, providing training designers, course conveners and facilitators with contextually informed insights.
- Full Text:
- Date Issued: 2020
Ethics and education as practices of freedom
- Authors: Tabensky, Pedro
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/305672 , vital:58602 , xlink:href="https://doi.org/10.1080/00131857.2020.1791822"
- Description: On the one hand, according to Richard Rorty, Paulo Freire and others, education is the practice of freedom. On the other hand, according to Michael Foucault, Mary Midgley and others, ethics is the practice of freedom. How, then, are education and ethics related to one another and what do these authors mean by ‘the practice of freedom’? In this piece, I argue that education and ethics are two mutually constitutive aspects of the practice of freedom. Individuals who are able to engage in this practice can most properly be said to be the authors of their lives, that is, individuals who, to borrow from Neil MacGregor, are able to find their ‘place in things’. To find our ‘place in things’ is to do the necessary educative work required for becoming the authors of our lives, that is, for self-actualization (as Rorty and John Dewey have argued). To take on the authorial role is, moreover, to be able effectively to take control of our lives, to organize them into unities for which we are individually responsible. This, according to Midgley, is precisely what it is to be ethical. This work, moreover, requires ongoing development, that is, education, in Dewey’s sense. I further argue that professional education and skills training cannot be understood properly in isolation from these broader educational aims and I criticize mainstream educational practices for not paying sufficient attention to the intimate relationship between the vocational and non-vocational aspects of education.
- Full Text:
- Date Issued: 2020
- Authors: Tabensky, Pedro
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/305672 , vital:58602 , xlink:href="https://doi.org/10.1080/00131857.2020.1791822"
- Description: On the one hand, according to Richard Rorty, Paulo Freire and others, education is the practice of freedom. On the other hand, according to Michael Foucault, Mary Midgley and others, ethics is the practice of freedom. How, then, are education and ethics related to one another and what do these authors mean by ‘the practice of freedom’? In this piece, I argue that education and ethics are two mutually constitutive aspects of the practice of freedom. Individuals who are able to engage in this practice can most properly be said to be the authors of their lives, that is, individuals who, to borrow from Neil MacGregor, are able to find their ‘place in things’. To find our ‘place in things’ is to do the necessary educative work required for becoming the authors of our lives, that is, for self-actualization (as Rorty and John Dewey have argued). To take on the authorial role is, moreover, to be able effectively to take control of our lives, to organize them into unities for which we are individually responsible. This, according to Midgley, is precisely what it is to be ethical. This work, moreover, requires ongoing development, that is, education, in Dewey’s sense. I further argue that professional education and skills training cannot be understood properly in isolation from these broader educational aims and I criticize mainstream educational practices for not paying sufficient attention to the intimate relationship between the vocational and non-vocational aspects of education.
- Full Text:
- Date Issued: 2020
Ethics in context
- Burningham, Kate, Venn, Susan, Hayward, Bronwyn, Aoyagi, Midori, Hasan, Mohammed Mehedi, Mattar, Helio, Schudel, Ingrid J, Yoshida, Aya
- Authors: Burningham, Kate , Venn, Susan , Hayward, Bronwyn , Aoyagi, Midori , Hasan, Mohammed Mehedi , Mattar, Helio , Schudel, Ingrid J , Yoshida, Aya
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/294364 , vital:57215 , xlink:href="https://doi.org/10.1080/13645579.2019.1672282"
- Description: Existing literatures have discussed both ethical issues in visual research with young people, and the problems associated with applying ‘universal’ ethical guidelines across varied cultural contexts. There has been little consideration, however, of specific issues raised in projects where visual research is being conducted with young people simultaneously in multiple national contexts. This paper contributes to knowledge in this area. We reflect on our experiences of planning and conducting the International CYCLES project involving photo elicitation with young people in Bangladesh, Brazil, India, Japan, New Zealand, South Africa and the UK. While some issues such as varying access to technology for taking and sharing photos and diverse cultural sensitivities around the use of photography were anticipated in advance, others were more unexpected. Balancing the need for methods to be appropriate, ethical and feasible within each setting with the desire for sufficient consistency across the project is challenging. We argue that an ‘ethics in context’ approach and an attitude of ‘methodological immaturity’ is critical in international visual research projects with young people.
- Full Text:
- Date Issued: 2020
- Authors: Burningham, Kate , Venn, Susan , Hayward, Bronwyn , Aoyagi, Midori , Hasan, Mohammed Mehedi , Mattar, Helio , Schudel, Ingrid J , Yoshida, Aya
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/294364 , vital:57215 , xlink:href="https://doi.org/10.1080/13645579.2019.1672282"
- Description: Existing literatures have discussed both ethical issues in visual research with young people, and the problems associated with applying ‘universal’ ethical guidelines across varied cultural contexts. There has been little consideration, however, of specific issues raised in projects where visual research is being conducted with young people simultaneously in multiple national contexts. This paper contributes to knowledge in this area. We reflect on our experiences of planning and conducting the International CYCLES project involving photo elicitation with young people in Bangladesh, Brazil, India, Japan, New Zealand, South Africa and the UK. While some issues such as varying access to technology for taking and sharing photos and diverse cultural sensitivities around the use of photography were anticipated in advance, others were more unexpected. Balancing the need for methods to be appropriate, ethical and feasible within each setting with the desire for sufficient consistency across the project is challenging. We argue that an ‘ethics in context’ approach and an attitude of ‘methodological immaturity’ is critical in international visual research projects with young people.
- Full Text:
- Date Issued: 2020
Evolving an Efficient and Effective Off-the-Shelf Computing Infrastructure for Rural Communities of South Africa
- Siebörger, Ingrid, Terzoli, Alfredo, Hodgkinson-Williams, Cheryl
- Authors: Siebörger, Ingrid , Terzoli, Alfredo , Hodgkinson-Williams, Cheryl
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430990 , vital:72734 , https://doi.org/10.1007/978-3-030-52014-4_5
- Description: Information Communication Technologies (ICTs) have diffused into al-most every area of life for citizens living in the Global North. Data is seen as a key element in the fourth industrial revolution and is the foundation of Information, Knowledge and Wisdom. Knowledge has become the new “make or break” asset and an inability to access the world’s data and technologies that facilitate access, synthesis and inter-rogation of data places one at a disadvantage. In 2013, the Department of Communications in South Africa announced a new national broad-band policy to promote the reduction of a digital divide and sup-port citi-zens and the economy in digital interactions. Implementation has thus far not been successful. Furthermore, the Broadband policy does not address how South Africans are to access the Internet once available. The Siyakhula Living Lab (SLL) provides an example of a computing infrastructure model for the introduction of ICTs into rural communities. Through the deployment of “broadband islands” and low-cost compu-ting infrastructure to promote both knowledge creation and consump-tion, access to the proposed ubiquitous Internet connectivity can be un-locked. However, the initial computing infrastructure deployed to the SLL suffers from a single point of failure. In this paper, we discuss al-ternative computing infrastructure configurations that were tested and deployed within the SLL in order to determine a more appropriate com-puting infrastructure model for the SLL and potentially other rural South African communities; such that learners, teachers and community members can be active contributors and consumers of data, infor-mation, knowledge and wisdom.
- Full Text:
- Date Issued: 2020
- Authors: Siebörger, Ingrid , Terzoli, Alfredo , Hodgkinson-Williams, Cheryl
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430990 , vital:72734 , https://doi.org/10.1007/978-3-030-52014-4_5
- Description: Information Communication Technologies (ICTs) have diffused into al-most every area of life for citizens living in the Global North. Data is seen as a key element in the fourth industrial revolution and is the foundation of Information, Knowledge and Wisdom. Knowledge has become the new “make or break” asset and an inability to access the world’s data and technologies that facilitate access, synthesis and inter-rogation of data places one at a disadvantage. In 2013, the Department of Communications in South Africa announced a new national broad-band policy to promote the reduction of a digital divide and sup-port citi-zens and the economy in digital interactions. Implementation has thus far not been successful. Furthermore, the Broadband policy does not address how South Africans are to access the Internet once available. The Siyakhula Living Lab (SLL) provides an example of a computing infrastructure model for the introduction of ICTs into rural communities. Through the deployment of “broadband islands” and low-cost compu-ting infrastructure to promote both knowledge creation and consump-tion, access to the proposed ubiquitous Internet connectivity can be un-locked. However, the initial computing infrastructure deployed to the SLL suffers from a single point of failure. In this paper, we discuss al-ternative computing infrastructure configurations that were tested and deployed within the SLL in order to determine a more appropriate com-puting infrastructure model for the SLL and potentially other rural South African communities; such that learners, teachers and community members can be active contributors and consumers of data, infor-mation, knowledge and wisdom.
- Full Text:
- Date Issued: 2020
Expansive learning in the leadership development of school learners
- Grant, Carolyn, Kajee, Farhana Amod
- Authors: Grant, Carolyn , Kajee, Farhana Amod
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281072 , vital:55689 , xlink:href="https://doi.org/10.1080/13603124.2020.1836405"
- Description: In many countries across the globe, and on the African continent in particular, young people do not have a voice in matters concerning their schooling. By virtue of their minor status, opportunities for participatory decision-making and leadership in schools are restricted, despite national policies to the contrary. This is all-too-often because leadership is (mis)understood as an adult phenomenon. In this article, we present a formative intervention, ‘Learners Lead’, which aimed at developing learner voice and leadership in learners through collective involvement in school change projects. Formulated as a documentary case study, data were generated from 95 research reports, the written assessments of the students registered for the Educational Leadership and Management elective within a postgraduate qualification in a South African university. Analysis drew on the pyramid of learner voice and the theory of expansive learning to examine if, and how, leadership development in learners occurred. The study found that expansive learning’s seven learning actions provided the necessary additional theoretical tools for understanding and unpacking the stages of leadership development as the school change projects unfolded. Implications for practice and research are discussed.
- Full Text:
- Date Issued: 2020
- Authors: Grant, Carolyn , Kajee, Farhana Amod
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281072 , vital:55689 , xlink:href="https://doi.org/10.1080/13603124.2020.1836405"
- Description: In many countries across the globe, and on the African continent in particular, young people do not have a voice in matters concerning their schooling. By virtue of their minor status, opportunities for participatory decision-making and leadership in schools are restricted, despite national policies to the contrary. This is all-too-often because leadership is (mis)understood as an adult phenomenon. In this article, we present a formative intervention, ‘Learners Lead’, which aimed at developing learner voice and leadership in learners through collective involvement in school change projects. Formulated as a documentary case study, data were generated from 95 research reports, the written assessments of the students registered for the Educational Leadership and Management elective within a postgraduate qualification in a South African university. Analysis drew on the pyramid of learner voice and the theory of expansive learning to examine if, and how, leadership development in learners occurred. The study found that expansive learning’s seven learning actions provided the necessary additional theoretical tools for understanding and unpacking the stages of leadership development as the school change projects unfolded. Implications for practice and research are discussed.
- Full Text:
- Date Issued: 2020
Exploring how a genetic attribution to disease relates to stigma experiences of Xhosa patients with schizophrenia in South Africa
- Matshabane, Olivia P, Campbell, Megan, Faure, Marlyn C, Marshall, Patricia A, Mayosi, Bongani M, Stein, Dan J, Appelbaum, Paul S, de Vries, Jantina
- Authors: Matshabane, Olivia P , Campbell, Megan , Faure, Marlyn C , Marshall, Patricia A , Mayosi, Bongani M , Stein, Dan J , Appelbaum, Paul S , de Vries, Jantina
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302487 , vital:58201 , xlink:href="https://doi.org/10.1007/s00127-020-01875-z"
- Description: Background: Over the past three decades, a range of international stakeholders have highlighted the possibility that genomic research may impact stigma associated with psychiatric disorders. Limited research has been conducted in Africa to investigate this relation. Method In the present study, using focus group discussions, we explored the relation between genetic attribution and stigma among 36 Xhosa people with schizophrenia. We addressed three main questions: (1) What causal beliefs do Xhosa people with schizophrenia use to explain their illness and to what extent do genetic explanations play a role in these beliefs? (2) What are the internalised stigma experiences of Xhosa people with schizophrenia? (3) How do genetic explanations relate to stigma experiences, if at all? Results Most participants were able to define genetics and some linked genetics to disease causation. Despite adequate knowledge of genetics and an emphasis on genetic explanations of schizophrenia in the study, most participants held a multitude of causal explanations including: psychosocial, environmental, and cultural. Moreover, participants rarely mentioned disease cause when describing their stigma experiences. Discussion For this population group, there was no straight-forward relation between a genetic attribution and stigma. Therefore, we did not fnd evidence that genetic attribution may signifcantly increase stigma. Although North American and European literature provides conficting evidence regarding this relation, there is increased consensus that biomedical explanations for psychiatric disorders may reduce blame. This study found evidence supporting that consensus. This study provides an empirical foundation to inform ongoing work on the psychosocial implications of psychiatric genomics research in non-Western contexts.
- Full Text:
- Date Issued: 2020
- Authors: Matshabane, Olivia P , Campbell, Megan , Faure, Marlyn C , Marshall, Patricia A , Mayosi, Bongani M , Stein, Dan J , Appelbaum, Paul S , de Vries, Jantina
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302487 , vital:58201 , xlink:href="https://doi.org/10.1007/s00127-020-01875-z"
- Description: Background: Over the past three decades, a range of international stakeholders have highlighted the possibility that genomic research may impact stigma associated with psychiatric disorders. Limited research has been conducted in Africa to investigate this relation. Method In the present study, using focus group discussions, we explored the relation between genetic attribution and stigma among 36 Xhosa people with schizophrenia. We addressed three main questions: (1) What causal beliefs do Xhosa people with schizophrenia use to explain their illness and to what extent do genetic explanations play a role in these beliefs? (2) What are the internalised stigma experiences of Xhosa people with schizophrenia? (3) How do genetic explanations relate to stigma experiences, if at all? Results Most participants were able to define genetics and some linked genetics to disease causation. Despite adequate knowledge of genetics and an emphasis on genetic explanations of schizophrenia in the study, most participants held a multitude of causal explanations including: psychosocial, environmental, and cultural. Moreover, participants rarely mentioned disease cause when describing their stigma experiences. Discussion For this population group, there was no straight-forward relation between a genetic attribution and stigma. Therefore, we did not fnd evidence that genetic attribution may signifcantly increase stigma. Although North American and European literature provides conficting evidence regarding this relation, there is increased consensus that biomedical explanations for psychiatric disorders may reduce blame. This study found evidence supporting that consensus. This study provides an empirical foundation to inform ongoing work on the psychosocial implications of psychiatric genomics research in non-Western contexts.
- Full Text:
- Date Issued: 2020
Fabrication of electrospun fibers from a porphyrin linked to polyacrylonitrile polymer for photocatalytic transformation of phenols
- Jones, Ben, Mafukidze, Donovan M, Nyokong, Tebello
- Authors: Jones, Ben , Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186196 , vital:44472 , xlink:href="https://doi.org/10.1016/j.molstruc.2020.128191"
- Description: A novel mono-porphyrin (2) was employed for the photodegradation of 4-chlorophenol and 4-n-nonylphenol at pH 10.60. A partially modified polyacrylonitrile (PAN) polymer was utilized only as a support system for the photosensitiser to allow the formation of a covalent linkage. Complex 2 showed singlet oxygen values of 0.70 in dimethyl formamide and when conjugated (2-PAN) showed 0.39 in water. When employed against 4-chlorophenol a degradation efficiency (η) of 29.1% was achieved at 0.20 mol L−1 over a period of 10 min. When employed against 4-n-nonylphenol we obtained a η of 26.7% at 0.17 mol L−1 over a period of 10 min.
- Full Text:
- Date Issued: 2020
- Authors: Jones, Ben , Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186196 , vital:44472 , xlink:href="https://doi.org/10.1016/j.molstruc.2020.128191"
- Description: A novel mono-porphyrin (2) was employed for the photodegradation of 4-chlorophenol and 4-n-nonylphenol at pH 10.60. A partially modified polyacrylonitrile (PAN) polymer was utilized only as a support system for the photosensitiser to allow the formation of a covalent linkage. Complex 2 showed singlet oxygen values of 0.70 in dimethyl formamide and when conjugated (2-PAN) showed 0.39 in water. When employed against 4-chlorophenol a degradation efficiency (η) of 29.1% was achieved at 0.20 mol L−1 over a period of 10 min. When employed against 4-n-nonylphenol we obtained a η of 26.7% at 0.17 mol L−1 over a period of 10 min.
- Full Text:
- Date Issued: 2020
Feminisms and decolonising psychology: Possibilities and challenges
- Macleod, Catriona I, Bhatia, Sunil, Liu, Wen
- Authors: Macleod, Catriona I , Bhatia, Sunil , Liu, Wen
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444314 , vital:74218 , xlink:href="https://doi.org/10.1177/0959353520932810"
- Description: In this special issue, we bring together papers that speak to feminisms in relation to decolonisation in the discipline of psychology. The six articles and two book reviews address a range of issues: race, citizenship, emancipatory politics, practising decolonial refusal, normalising slippery subjectivity, Islamic anti-patriarchal liberation psychology, and decolonisation of the hijab. In this editorial we outline the papers’ contributions to discussions on understanding decolonisation, how feminisms and decolonisation speak to each other, and the implications of the papers for feminist decolonising psychology. Together the papers highlight the importance of undermining the gendered coloniality of power, knowledge and being. The interweaving of feminisms and decolonising efforts can be achieved through: each mutually informing and shaping the other, conducting intersectional analyses, and drawing on transnational feminisms. Guiding principles for feminist decolonising psychology include: undermining the patriarchal colonialist legacy of mainstream psychological science; connecting gendered coloniality with other systems of power such as globalisation; investigating topics that surface the intertwining of colonialist and gendered power relations; using research methods that dovetail with feminist decolonising psychology; and focussing praxis on issues that enable decolonisation. Given the complexities of the coloniality and patriarchy of power-knowledge-being, feminist decolonising psychology may fail. The issues raised in this special issue point to why it mustn’t.
- Full Text:
- Date Issued: 2020
- Authors: Macleod, Catriona I , Bhatia, Sunil , Liu, Wen
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444314 , vital:74218 , xlink:href="https://doi.org/10.1177/0959353520932810"
- Description: In this special issue, we bring together papers that speak to feminisms in relation to decolonisation in the discipline of psychology. The six articles and two book reviews address a range of issues: race, citizenship, emancipatory politics, practising decolonial refusal, normalising slippery subjectivity, Islamic anti-patriarchal liberation psychology, and decolonisation of the hijab. In this editorial we outline the papers’ contributions to discussions on understanding decolonisation, how feminisms and decolonisation speak to each other, and the implications of the papers for feminist decolonising psychology. Together the papers highlight the importance of undermining the gendered coloniality of power, knowledge and being. The interweaving of feminisms and decolonising efforts can be achieved through: each mutually informing and shaping the other, conducting intersectional analyses, and drawing on transnational feminisms. Guiding principles for feminist decolonising psychology include: undermining the patriarchal colonialist legacy of mainstream psychological science; connecting gendered coloniality with other systems of power such as globalisation; investigating topics that surface the intertwining of colonialist and gendered power relations; using research methods that dovetail with feminist decolonising psychology; and focussing praxis on issues that enable decolonisation. Given the complexities of the coloniality and patriarchy of power-knowledge-being, feminist decolonising psychology may fail. The issues raised in this special issue point to why it mustn’t.
- Full Text:
- Date Issued: 2020
Fertility, childbirth and parenting Defining sexual and gender relations
- Macleod, Catriona I, Morison, Tracy
- Authors: Macleod, Catriona I , Morison, Tracy
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434112 , vital:73032 , ISBN 9781108460903 , https://biblio.co.uk/book/cambridge-handbook-international-psychology-women-fan-ny/d/1521282285?aid=frggad_source=1gclid=CjwKCAjwz42xBhB9EiwA48pT70yXdV4oAp4StC49UDVfIuCISAVjZGdeibEiPkf_CNtGgog6bJ7iDxoCgSIQAvD_BwE
- Description: Major historical shifts in the field of fertility, childbirth and parenting have implications for feminist psychologists working on these topics. These shifts include approaches to sexuality and reproduction: a population control emphasis in the late 1940s, a reproductive rights paradigm in the 1990s, and progression from reproductive rights to reproductive justice. Feminist psychologists must traverse the political landscape created by these broad approaches. In this chapter, we suggest ways in which such engagement may be facilitated through examination of mainstream assumptions and outcomes and the use of nuanced feminist research. Drawing from transnational feminisms, the principles of reproductive justice, and examples of research and interventions in reproductive decisionmaking, abortion, obstetric violence, ‘deviant’ (m)others, early reproduction and contraception, we argue that feminist psychology should attend to both global and crosscutting power relations concerning fertility and reproduction, as well as localised dynamics.
- Full Text:
- Date Issued: 2020
- Authors: Macleod, Catriona I , Morison, Tracy
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434112 , vital:73032 , ISBN 9781108460903 , https://biblio.co.uk/book/cambridge-handbook-international-psychology-women-fan-ny/d/1521282285?aid=frggad_source=1gclid=CjwKCAjwz42xBhB9EiwA48pT70yXdV4oAp4StC49UDVfIuCISAVjZGdeibEiPkf_CNtGgog6bJ7iDxoCgSIQAvD_BwE
- Description: Major historical shifts in the field of fertility, childbirth and parenting have implications for feminist psychologists working on these topics. These shifts include approaches to sexuality and reproduction: a population control emphasis in the late 1940s, a reproductive rights paradigm in the 1990s, and progression from reproductive rights to reproductive justice. Feminist psychologists must traverse the political landscape created by these broad approaches. In this chapter, we suggest ways in which such engagement may be facilitated through examination of mainstream assumptions and outcomes and the use of nuanced feminist research. Drawing from transnational feminisms, the principles of reproductive justice, and examples of research and interventions in reproductive decisionmaking, abortion, obstetric violence, ‘deviant’ (m)others, early reproduction and contraception, we argue that feminist psychology should attend to both global and crosscutting power relations concerning fertility and reproduction, as well as localised dynamics.
- Full Text:
- Date Issued: 2020
First record of an indigenous South African parasitoid wasp on an imported biological control agent, the water hyacinth hopper
- Kraus, Emily C, Coetzee, Julie A, van Noort, Simon, Olmi, Massimo
- Authors: Kraus, Emily C , Coetzee, Julie A , van Noort, Simon , Olmi, Massimo
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417700 , vital:71479 , xlink:href="https://doi.org/10.1080/09583157.2019.1660306"
- Description: Water hyacinth, Pontederia crassipes (Martius) [≡Eichhornia crassip es (Martius) Solms-Laubach] (Pontederiaceae), is native to South America, but has expanded its range to many other regions of the world including South Africa. Megamelus scutellaris Berg (Hemiptera: Delphacidae) was released as a biological control agent and has established in several regions. Recently, the indigenous species Echthrodelphax migratorius Benoit, (Hymenoptera: Dryinidae) was discovered in South Africa parasitising M. scutellaris. This newly discovered relationship might have repercussions for the efficacy of biological control of water hyacinth by the delphacid. The wasp may negatively impact M. scutellaris populations making it difficult for the agent to successfully manage the invasive weed. Contrarily, the parasitoid may be beneficial by keeping the M. scutellaris populations stable, serving as a natural enemy.
- Full Text:
- Date Issued: 2020
- Authors: Kraus, Emily C , Coetzee, Julie A , van Noort, Simon , Olmi, Massimo
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417700 , vital:71479 , xlink:href="https://doi.org/10.1080/09583157.2019.1660306"
- Description: Water hyacinth, Pontederia crassipes (Martius) [≡Eichhornia crassip es (Martius) Solms-Laubach] (Pontederiaceae), is native to South America, but has expanded its range to many other regions of the world including South Africa. Megamelus scutellaris Berg (Hemiptera: Delphacidae) was released as a biological control agent and has established in several regions. Recently, the indigenous species Echthrodelphax migratorius Benoit, (Hymenoptera: Dryinidae) was discovered in South Africa parasitising M. scutellaris. This newly discovered relationship might have repercussions for the efficacy of biological control of water hyacinth by the delphacid. The wasp may negatively impact M. scutellaris populations making it difficult for the agent to successfully manage the invasive weed. Contrarily, the parasitoid may be beneficial by keeping the M. scutellaris populations stable, serving as a natural enemy.
- Full Text:
- Date Issued: 2020
Forays into contemporary South African theatre
- Authors: Krueger, Anton
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229578 , vital:49689 , xlink:href="https://doi.org/10.1080/10137548.2021.1963112"
- Description: Trying to keep up with what is going on in South African theatre today is an endlessly renewing process. The word ‘foray’ has associations of brief incursions into foreign territory. It’s an almost hesitant word, a venture into unexplored terrain. This hesitation feels apt in the sense that (at the time of writing), any description of a pre-Covid theatre is bound to feel strange. The landscape has shifted, and nobody is quite sure how things will look in a year from now. Nevertheless, this is a rich compendium of relatively recent theatre, as seen from within the country and also from the vantage of a global perspective. Almost all of the essays are drawn from a 2017 conference held in Brussels at the Université Libre de Bruxelles, called: ‘New Stage Idioms: South African Drama, Theatre and Performance in the Twenty-first Century.’Although the tone remains scholarly, the inclusion of different kinds of writers – not only academics but activists, playwrights and journalists – prevents the work from becoming overly dry.
- Full Text:
- Date Issued: 2020
- Authors: Krueger, Anton
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229578 , vital:49689 , xlink:href="https://doi.org/10.1080/10137548.2021.1963112"
- Description: Trying to keep up with what is going on in South African theatre today is an endlessly renewing process. The word ‘foray’ has associations of brief incursions into foreign territory. It’s an almost hesitant word, a venture into unexplored terrain. This hesitation feels apt in the sense that (at the time of writing), any description of a pre-Covid theatre is bound to feel strange. The landscape has shifted, and nobody is quite sure how things will look in a year from now. Nevertheless, this is a rich compendium of relatively recent theatre, as seen from within the country and also from the vantage of a global perspective. Almost all of the essays are drawn from a 2017 conference held in Brussels at the Université Libre de Bruxelles, called: ‘New Stage Idioms: South African Drama, Theatre and Performance in the Twenty-first Century.’Although the tone remains scholarly, the inclusion of different kinds of writers – not only academics but activists, playwrights and journalists – prevents the work from becoming overly dry.
- Full Text:
- Date Issued: 2020
Formulation and Characterisation of a Combination Captopril and Hydrochlorothiazide Microparticulate Dosage Form
- Chikukwa, Mellisa T R, Walker, Roderick B, Khamanga, Sandile M
- Authors: Chikukwa, Mellisa T R , Walker, Roderick B , Khamanga, Sandile M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183200 , vital:43926 , xlink:href="https://doi.org/10.3390/pharmaceutics12080712"
- Description: Cardiovascular diseases such as hypertension and cardiac failure in South African children and adolescents are effectively managed long term, using a combination treatment of captopril and hydrochlorothiazide. The majority of commercially available pharmaceutical products are designed for adult patients and require extemporaneous manipulation, prior to administration to paediatric patients. There is a need to develop an age appropriate microparticulate dosing technology that is easy to swallow, dose and alter doses whilst overcoming the pharmacokinetic challenges of short half-life and biphasic pharmacokinetic disposition exhibited by hydrochlorothiazide and captopril. An emulsion solvent evaporation approach using different combinations of polymers was used to manufacture captopril and hydrochlorothiazide microparticles. Design of experiments was used to develop and analyse experimental data, and identifyoptimum formulation and process conditions for the preparation of the microparticles. Characterisation studies to establish encapsulation efficiency, in vitro release, shape, size and morphology of the microparticles were undertaken. The microparticles produced were in the micrometre size range, with an encapsulation efficiency >75% for both hydrochlorothiazide and captopril. The microparticulate technology is able to offer potential resolution to the half-life mediated dosing frequency of captopril as sustained release of the molecule was observed over a 12-h period. The release of hydrochlorothiazide of >80% suggests an improvement in solubility limited dissolution.
- Full Text:
- Date Issued: 2020
- Authors: Chikukwa, Mellisa T R , Walker, Roderick B , Khamanga, Sandile M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183200 , vital:43926 , xlink:href="https://doi.org/10.3390/pharmaceutics12080712"
- Description: Cardiovascular diseases such as hypertension and cardiac failure in South African children and adolescents are effectively managed long term, using a combination treatment of captopril and hydrochlorothiazide. The majority of commercially available pharmaceutical products are designed for adult patients and require extemporaneous manipulation, prior to administration to paediatric patients. There is a need to develop an age appropriate microparticulate dosing technology that is easy to swallow, dose and alter doses whilst overcoming the pharmacokinetic challenges of short half-life and biphasic pharmacokinetic disposition exhibited by hydrochlorothiazide and captopril. An emulsion solvent evaporation approach using different combinations of polymers was used to manufacture captopril and hydrochlorothiazide microparticles. Design of experiments was used to develop and analyse experimental data, and identifyoptimum formulation and process conditions for the preparation of the microparticles. Characterisation studies to establish encapsulation efficiency, in vitro release, shape, size and morphology of the microparticles were undertaken. The microparticles produced were in the micrometre size range, with an encapsulation efficiency >75% for both hydrochlorothiazide and captopril. The microparticulate technology is able to offer potential resolution to the half-life mediated dosing frequency of captopril as sustained release of the molecule was observed over a 12-h period. The release of hydrochlorothiazide of >80% suggests an improvement in solubility limited dissolution.
- Full Text:
- Date Issued: 2020
Formulation optimization of smart thermosetting lamotrigine loaded hydrogels using response surface methodology, box benhken design and artificial neural networks
- Melamane, Siyabonga, Walker, Roderick B, Khamanga, Sandile M
- Authors: Melamane, Siyabonga , Walker, Roderick B , Khamanga, Sandile M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183265 , vital:43936 , xlink:href="https://doi.org/10.1080/03639045.2020.1791163"
- Description: The aim of this research was to develop lamotrigine containing thermosetting hydrogel for intranasal administration to manage and treat generalized epilepsy. Thermosetting hydrogels were prepared using different ratios of poloxamer 407 (L127), poloxamer 188 (L68) and CarbopolVR 974 P NF (C974) using the cold production process. The in situ thermosetting hydrogel was optimized using Box Behken design. Co-solvency approach was used to increase the solubility of lamotrigine by dissolving it in propylene glycol and polyethylene glycol 400 (0.2: 0.8) and the resultant solution was incorporated in the hydrogel to manufacture an LTG hydrogel. The presence of a higher amount of L127 resulted in higher viscosity at 22 0C and 34 0C and decreased the overall release of LTG. An increase in the amount of C974 resulted in a decrease in the pH of the hydrogel. The results show that formulations F10, F12, F13, F14, F15, F16 and F17 exhibited acceptable thermosetting behavior, pH and released adequate Lamotrigine above the minimum effective concentration to treat generalized epilepsy. The optimized formulation exhibited acceptable thermosetting behavior, pH and lamotrigine release but formed a stiff gel at 22 0C. The average LTG content of the optimized hydrogel was 5.00 ± 0.0225mg/ml with % recovery of 99.17%. The amount of LTG released at 12 h from the optimized hydrogel was 3.21 ± 0.0155mg and will be therapeutically effective in the brain after absorption via the olfactory region in the nasal cavity.
- Full Text:
- Date Issued: 2020
- Authors: Melamane, Siyabonga , Walker, Roderick B , Khamanga, Sandile M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183265 , vital:43936 , xlink:href="https://doi.org/10.1080/03639045.2020.1791163"
- Description: The aim of this research was to develop lamotrigine containing thermosetting hydrogel for intranasal administration to manage and treat generalized epilepsy. Thermosetting hydrogels were prepared using different ratios of poloxamer 407 (L127), poloxamer 188 (L68) and CarbopolVR 974 P NF (C974) using the cold production process. The in situ thermosetting hydrogel was optimized using Box Behken design. Co-solvency approach was used to increase the solubility of lamotrigine by dissolving it in propylene glycol and polyethylene glycol 400 (0.2: 0.8) and the resultant solution was incorporated in the hydrogel to manufacture an LTG hydrogel. The presence of a higher amount of L127 resulted in higher viscosity at 22 0C and 34 0C and decreased the overall release of LTG. An increase in the amount of C974 resulted in a decrease in the pH of the hydrogel. The results show that formulations F10, F12, F13, F14, F15, F16 and F17 exhibited acceptable thermosetting behavior, pH and released adequate Lamotrigine above the minimum effective concentration to treat generalized epilepsy. The optimized formulation exhibited acceptable thermosetting behavior, pH and lamotrigine release but formed a stiff gel at 22 0C. The average LTG content of the optimized hydrogel was 5.00 ± 0.0225mg/ml with % recovery of 99.17%. The amount of LTG released at 12 h from the optimized hydrogel was 3.21 ± 0.0155mg and will be therapeutically effective in the brain after absorption via the olfactory region in the nasal cavity.
- Full Text:
- Date Issued: 2020
Fucoidan from Ecklonia maxima is a powerful inhibitor of the diabetes-related enzyme, Éø-glucosidase
- Daub, Chantal D, Mabate, Blessing, Malgas, Samkelo, Pletschke, Brett I
- Authors: Daub, Chantal D , Mabate, Blessing , Malgas, Samkelo , Pletschke, Brett I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425982 , vital:72304 , xlink:href="https://doi.org/10.1016/j.ijbiomac.2020.02.161"
- Description: Ecklonia maxima, an endemic South African seaweed, is a potential source of beneficial bioactive compounds. Among these compounds, fucoidan, a sulphated polysaccharide has a wide range of bioactivities including anti-diabetic activity. In this study, fucoidan was extracted from E. maxima by the hot water extraction method and then characterised by colorimetric assays for sugar composition. The extraction from E. maxima yielded 6.89% fucoidan which was found to contain 4.45 ± 0.25% L-fucose and 6.01 ± 0.53% sulphate. The water extracted E. maxima fucoidan had a low molecular weight of approximately 10 kDa. Structural studies (FT-IR, NMR and XRD) confirmed the structure and integrity of the fucoidan to be similar to previously studied fucoidans in literature. Finally, the activities of starch digestive enzymes; α-amylase and α-glucosidase, were investigated in the presence of the E. maxima fucoidan extract. Fucoidan from E. maxima was observed to be a potent mixed-type inhibitor of α-glucosidase with an IC50 range of 0.27–0.31 mg.ml-1, which was significantly lower than the commercial anti-diabetic standard, acarbose. Our present study demonstrated that fucoidan from E. maxima is a more powerful inhibitor compared to some standard anti-diabetic compounds and thus shows great potential for managing type 2 diabetes.
- Full Text:
- Date Issued: 2020
Fucoidan from Ecklonia maxima is a powerful inhibitor of the diabetes-related enzyme, Éø-glucosidase
- Authors: Daub, Chantal D , Mabate, Blessing , Malgas, Samkelo , Pletschke, Brett I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425982 , vital:72304 , xlink:href="https://doi.org/10.1016/j.ijbiomac.2020.02.161"
- Description: Ecklonia maxima, an endemic South African seaweed, is a potential source of beneficial bioactive compounds. Among these compounds, fucoidan, a sulphated polysaccharide has a wide range of bioactivities including anti-diabetic activity. In this study, fucoidan was extracted from E. maxima by the hot water extraction method and then characterised by colorimetric assays for sugar composition. The extraction from E. maxima yielded 6.89% fucoidan which was found to contain 4.45 ± 0.25% L-fucose and 6.01 ± 0.53% sulphate. The water extracted E. maxima fucoidan had a low molecular weight of approximately 10 kDa. Structural studies (FT-IR, NMR and XRD) confirmed the structure and integrity of the fucoidan to be similar to previously studied fucoidans in literature. Finally, the activities of starch digestive enzymes; α-amylase and α-glucosidase, were investigated in the presence of the E. maxima fucoidan extract. Fucoidan from E. maxima was observed to be a potent mixed-type inhibitor of α-glucosidase with an IC50 range of 0.27–0.31 mg.ml-1, which was significantly lower than the commercial anti-diabetic standard, acarbose. Our present study demonstrated that fucoidan from E. maxima is a more powerful inhibitor compared to some standard anti-diabetic compounds and thus shows great potential for managing type 2 diabetes.
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- Date Issued: 2020