Mitigating Climate Change: The Influence of Arbuscular Mycorrhizal Fungi on Maize Production and Food Security
- Maússe-Sitoe, Silvia N D, Dames, Joanna F
- Authors: Maússe-Sitoe, Silvia N D , Dames, Joanna F
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/453465 , vital:75256 , ISBN 978-1-83768-091-7 , https://www.intechopen.com/chapters/84486
- Description: Anthropogenic activities have contributed to the increased atmospheric concentration of greenhouse gases, which are an important contributor to climate change. From 1940 to 2004, global emissions increased by 70%, and projections suggest a continual increase by 2050 due to agriculture, forestry, and other land uses. Arbuscular mycorrhizal (AM) fungi are ubiquitous in undisturbed soils and form a symbiotic relationship with various plants. The relationship that enhances nutrient uptake and plant growth, among other benefits, is well known. Several soil management practices employed in agriculture adversely affect the symbiosis. Zea mays (maize) provides 30% of total caloric intake to 4.5 billion people worldwide and is an important staple crop, vulnerable to climate change. Higher temperatures can result in increased water demand, while changes in precipitation can result in crop failure. AM fungi can be applied as inoculants to maize. Resulting in improved plant growth, yield, and nutrient uptake and providing superior food quality properties, such as increased antioxidants, vitamins, and minerals. AM fungi are considered a crucial biotechnological tool in crop production. This review illustrates their essential role in sustainable maize production and emphasizes the need to maintain AM fungal communities in the soil to mitigate the effects of climate change.
- Full Text:
- Date Issued: 2022
- Authors: Maússe-Sitoe, Silvia N D , Dames, Joanna F
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/453465 , vital:75256 , ISBN 978-1-83768-091-7 , https://www.intechopen.com/chapters/84486
- Description: Anthropogenic activities have contributed to the increased atmospheric concentration of greenhouse gases, which are an important contributor to climate change. From 1940 to 2004, global emissions increased by 70%, and projections suggest a continual increase by 2050 due to agriculture, forestry, and other land uses. Arbuscular mycorrhizal (AM) fungi are ubiquitous in undisturbed soils and form a symbiotic relationship with various plants. The relationship that enhances nutrient uptake and plant growth, among other benefits, is well known. Several soil management practices employed in agriculture adversely affect the symbiosis. Zea mays (maize) provides 30% of total caloric intake to 4.5 billion people worldwide and is an important staple crop, vulnerable to climate change. Higher temperatures can result in increased water demand, while changes in precipitation can result in crop failure. AM fungi can be applied as inoculants to maize. Resulting in improved plant growth, yield, and nutrient uptake and providing superior food quality properties, such as increased antioxidants, vitamins, and minerals. AM fungi are considered a crucial biotechnological tool in crop production. This review illustrates their essential role in sustainable maize production and emphasizes the need to maintain AM fungal communities in the soil to mitigate the effects of climate change.
- Full Text:
- Date Issued: 2022
Mixed-species flocks of insectivorous birds (‘bird parties’) in Afrotropical forests and woodlands: a review
- Authors: Craig, Adrian J F K
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449420 , vital:74820 , https://doi.org/10.2989/00306525.2022.2064930
- Description: Mixed-species flocks of foraging insectivorous birds are found worldwide and have been best studied in the Neotropical region. A survey of the published literature reveals that mixed-species flocks (often termed ‘bird parties’) comprised of 2–30 species and sometimes >70 individual birds are regularly encountered in forest and woodland habitats throughout the Afrotropical region. On mainland Africa, >600 species representing 59 bird families have been reported in such flocks, and for at least 300 species foraging in such flocks may constitute an important part of their feeding activity. In Madagascar, >60 species of 19 families have been recorded in mixed-species flocks, with more than 40 species frequent participants. These foraging parties are dominated by gleaning and sallying insectivorous birds, with other feeding guilds represented by fewer species and individuals.
- Full Text:
- Date Issued: 2022
- Authors: Craig, Adrian J F K
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449420 , vital:74820 , https://doi.org/10.2989/00306525.2022.2064930
- Description: Mixed-species flocks of foraging insectivorous birds are found worldwide and have been best studied in the Neotropical region. A survey of the published literature reveals that mixed-species flocks (often termed ‘bird parties’) comprised of 2–30 species and sometimes >70 individual birds are regularly encountered in forest and woodland habitats throughout the Afrotropical region. On mainland Africa, >600 species representing 59 bird families have been reported in such flocks, and for at least 300 species foraging in such flocks may constitute an important part of their feeding activity. In Madagascar, >60 species of 19 families have been recorded in mixed-species flocks, with more than 40 species frequent participants. These foraging parties are dominated by gleaning and sallying insectivorous birds, with other feeding guilds represented by fewer species and individuals.
- Full Text:
- Date Issued: 2022
Neoliberalism’s conditioning effects on the university and the example of proctoring during COVID-19 and since
- Authors: McKenna, Sioux
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426929 , vital:72401 , xlink:href="https://doi.org/10.1080/14767430.2022.2100612"
- Description: Neoliberalism has shaped the academy in ways that constrain its potential as a public good. Neoliberalism is based on the assumption that, by submitting to the so-called neutral forces of the market, wealth can be created alongside the achievement of equality and efficiency. Although this assumption is demonstrably false, neoliberalism remains politically powerful. As an example, this article discusses how neoliberalism has enabled the rapid uptake of proctoring software during the covid pandemic and since. ‘Proctoring' is the online monitoring of students’ behaviour as they sit for exams. Many within the academy consider proctoring software to be dehumanizing – essentially legalized spyware. They argue that the software invades privacy and is inherently racist and ableist, amongst other things. It is hoped that by understanding how structural forces such as neoliberalism affect both our agency and university activities, frequently against the common good, strategies can be developed to change these structures.
- Full Text:
- Date Issued: 2022
- Authors: McKenna, Sioux
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426929 , vital:72401 , xlink:href="https://doi.org/10.1080/14767430.2022.2100612"
- Description: Neoliberalism has shaped the academy in ways that constrain its potential as a public good. Neoliberalism is based on the assumption that, by submitting to the so-called neutral forces of the market, wealth can be created alongside the achievement of equality and efficiency. Although this assumption is demonstrably false, neoliberalism remains politically powerful. As an example, this article discusses how neoliberalism has enabled the rapid uptake of proctoring software during the covid pandemic and since. ‘Proctoring' is the online monitoring of students’ behaviour as they sit for exams. Many within the academy consider proctoring software to be dehumanizing – essentially legalized spyware. They argue that the software invades privacy and is inherently racist and ableist, amongst other things. It is hoped that by understanding how structural forces such as neoliberalism affect both our agency and university activities, frequently against the common good, strategies can be developed to change these structures.
- Full Text:
- Date Issued: 2022
Not there yet: knowledge building in educational development ten years on
- Authors: Boughey, Chrissie
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426954 , vital:72403 , xlink:href="https://doi.org/10.1080/13562517.2022.2121158"
- Description: This paper responds to a question posed by [Shay, Suellen. 2012. “Educational Development as a Field: Are We There Yet?” Higher Education Research and Development 31 (3): 311–323. doii:10.1080/07294360.2011.631520] about the status of knowledge building in the field of Educational Development. In her paper, Shay critiques knowledge produced in the field arguing that it is ‘codified practice’ [Gamble, Jeanne. 2001. “Modelling the Invisible: The Pedagogy of Craft Apprenticeship.” Studies in Continuing Education 23 (2): 185–200. doii:10.1080/01580370120101957; Gamble, Jeanne. 2004. “Retrieving the General from the Particular: The Structure of Craft Knowledge.” In Reading Bernstein, Researching Bernstein, edited by J. Muller, B. Davies, and A. Morais, 189–203. Abingdon: Routledge; Gamble, Jeanne. 2006. “Theory and Practice in the Vocational Curriculum.” In Knowledge, Curriculum and Qualifications in South African Further Education, edited by M. Young and J. Gamble, 87–103. Pretoria: HSRC Press] rather than applied theory which could succeed in reconceptualising problems rather than simply trying to address them. This paper draws on a review of research produced in the field in recent years in South Africa to argue that, although some work does result in the reconceptualision of problems the higher education, it is limited in that (i) it has been produced by a relatively small group of practitioners located at a few universities and (ii) draws on theory developed in the Global North. The paper then proceeds to offer some tentative suggestions for the way future work aimed at knowledge building could proceed.
- Full Text:
- Date Issued: 2022
- Authors: Boughey, Chrissie
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426954 , vital:72403 , xlink:href="https://doi.org/10.1080/13562517.2022.2121158"
- Description: This paper responds to a question posed by [Shay, Suellen. 2012. “Educational Development as a Field: Are We There Yet?” Higher Education Research and Development 31 (3): 311–323. doii:10.1080/07294360.2011.631520] about the status of knowledge building in the field of Educational Development. In her paper, Shay critiques knowledge produced in the field arguing that it is ‘codified practice’ [Gamble, Jeanne. 2001. “Modelling the Invisible: The Pedagogy of Craft Apprenticeship.” Studies in Continuing Education 23 (2): 185–200. doii:10.1080/01580370120101957; Gamble, Jeanne. 2004. “Retrieving the General from the Particular: The Structure of Craft Knowledge.” In Reading Bernstein, Researching Bernstein, edited by J. Muller, B. Davies, and A. Morais, 189–203. Abingdon: Routledge; Gamble, Jeanne. 2006. “Theory and Practice in the Vocational Curriculum.” In Knowledge, Curriculum and Qualifications in South African Further Education, edited by M. Young and J. Gamble, 87–103. Pretoria: HSRC Press] rather than applied theory which could succeed in reconceptualising problems rather than simply trying to address them. This paper draws on a review of research produced in the field in recent years in South Africa to argue that, although some work does result in the reconceptualision of problems the higher education, it is limited in that (i) it has been produced by a relatively small group of practitioners located at a few universities and (ii) draws on theory developed in the Global North. The paper then proceeds to offer some tentative suggestions for the way future work aimed at knowledge building could proceed.
- Full Text:
- Date Issued: 2022
Novel cationic-chalcone phthalocyanines for photodynamic therapy eradication of S. aureus and E. coli bacterial biofilms and MCF-7 breast cancer
- Openda, Yolande Ikala, Babu, Balaji, Nyokong, Tebello
- Authors: Openda, Yolande Ikala , Babu, Balaji , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300129 , vital:57895 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.102863"
- Description: New tetrasubstituted zinc (II) and indium (III) phthalocyanines bearing dimethylamino chalcone group (complexes 3 and 4) as well as their quaternized analogs (3a and 4a) have been assessed for their photodynamic therapy (PDT) of cancer as well as photodynamic antimicrobial chemotherapy activities against biofilms and planktonic cultures of pathogenic bacteria of Staphylococcus aureus and Escherichia coli. Compared to the non-quaternized phthalocyanines 3 and 4, the cationic phthalocyanines 3a and 4a exhibit a higher photodynamic inactivation against the planktonic cells with log reduction values above 9 at a concentration of 1.25 µM. This was attributed to the positive charge which enhances cellular uptake. More interestingly, 3a and 4a show a higher photodynamic inactivation (less than 3% of S. aureus survived) on their biofilm counterparts thanks to their stronger affinity to these cells. 3a and 4a Pcs also exhibited interesting PDT activity against MCF-7 cancer cells giving IC50 values of 17.9 and 7.4 μM, respectively following 15 min irradiation. The obtained results in this work show that the positively charged phthalocyanines 3a and 4a are potential antibacterial photosensitizers that show some selectivity toward the Gram-positive and Gram-negative bacteria as well as MCF-7 breasts cancer cells.
- Full Text:
- Date Issued: 2022
- Authors: Openda, Yolande Ikala , Babu, Balaji , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300129 , vital:57895 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.102863"
- Description: New tetrasubstituted zinc (II) and indium (III) phthalocyanines bearing dimethylamino chalcone group (complexes 3 and 4) as well as their quaternized analogs (3a and 4a) have been assessed for their photodynamic therapy (PDT) of cancer as well as photodynamic antimicrobial chemotherapy activities against biofilms and planktonic cultures of pathogenic bacteria of Staphylococcus aureus and Escherichia coli. Compared to the non-quaternized phthalocyanines 3 and 4, the cationic phthalocyanines 3a and 4a exhibit a higher photodynamic inactivation against the planktonic cells with log reduction values above 9 at a concentration of 1.25 µM. This was attributed to the positive charge which enhances cellular uptake. More interestingly, 3a and 4a show a higher photodynamic inactivation (less than 3% of S. aureus survived) on their biofilm counterparts thanks to their stronger affinity to these cells. 3a and 4a Pcs also exhibited interesting PDT activity against MCF-7 cancer cells giving IC50 values of 17.9 and 7.4 μM, respectively following 15 min irradiation. The obtained results in this work show that the positively charged phthalocyanines 3a and 4a are potential antibacterial photosensitizers that show some selectivity toward the Gram-positive and Gram-negative bacteria as well as MCF-7 breasts cancer cells.
- Full Text:
- Date Issued: 2022
One and done, or a bundle and stumble? an exploration of assessment methods in undergraduate science curricula
- Authors: Edwards, Shelley
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/461539 , vital:76211 , xlink:href="https://doi.org/10.2478/atd-2022-0023"
- Description: Assessment, historically, has been done in a summative manner in post-secondary education (HE). Whilst useful for the purposes of grading and assessment of competency, there is also increasing pressure from post-secondary education institutions to meet certain standards in terms of education quality and graduate numbers, putting pressure on teachers to produce evidence of students’ level of understanding and thus putting a greater emphasis on the use of summative assessments. The formative assessment approach for student learning is preferable in some fields, but how useful is this format for the science subjects?
- Full Text:
- Date Issued: 2022
- Authors: Edwards, Shelley
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/461539 , vital:76211 , xlink:href="https://doi.org/10.2478/atd-2022-0023"
- Description: Assessment, historically, has been done in a summative manner in post-secondary education (HE). Whilst useful for the purposes of grading and assessment of competency, there is also increasing pressure from post-secondary education institutions to meet certain standards in terms of education quality and graduate numbers, putting pressure on teachers to produce evidence of students’ level of understanding and thus putting a greater emphasis on the use of summative assessments. The formative assessment approach for student learning is preferable in some fields, but how useful is this format for the science subjects?
- Full Text:
- Date Issued: 2022
Photo-and thermoresponsive N-salicylideneaniline derivatives: solid-state studies and structural aspects
- Hulushe, Siyabonga T, Malan, Frederick P, Hosten, Eric C, Lobb, Kevin A, Khanye, Setshaba D, Watkins, Gareth M
- Authors: Hulushe, Siyabonga T , Malan, Frederick P , Hosten, Eric C , Lobb, Kevin A , Khanye, Setshaba D , Watkins, Gareth M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451137 , vital:75021 , xlink:href="https://pubs.rsc.org/en/content/articlehtml/2022/nj/d1nj03056f"
- Description: N-Salicylideneaniline (SA) and its derivatives are known to possess chromism upon exposure to external stimuli. Herein, we present mechanochemical synthesis of a series of photo-and thermoresponsive SAderivatives and report on solid-state stabilisation of their tautomeric forms either by change in temperature or by photoirradiation. The influence of UV light on proton transfer between the enol-imine (EI) and keto-amine (KA) forms was investigated at l1 = 254 and l2 = 365 nm. Differential scanning calorimetry (DSC) measurements provided extra information on the thermodynamic relationship between the prototropic tautomers, and their exposition to liquid nitrogen, combined with variable temperature single-crystal X-ray diffraction (VT-SCXRD) and spectroscopic data, ascertained structural reasons for the intrinsic thermo-optical properties of the compounds. A series of structural determinations between 150 and 300 K further shed light on the thermomechanical behaviour exhibited by the thermoresponsive compounds. By virtue of calorimetry we were able to demonstrate proton transfer via the intramolecular ON hydrogen bond over the temperature range 193–453 K. This present work demonstrates the importance of applying complementary analytical techniques and appropriate approaches for understanding the switching behaviour between the EI and KA forms. Furthermore, the assertion that it is predominantly the planarity (j o 251) that determines thermochromaticity is questioned.
- Full Text:
- Date Issued: 2022
- Authors: Hulushe, Siyabonga T , Malan, Frederick P , Hosten, Eric C , Lobb, Kevin A , Khanye, Setshaba D , Watkins, Gareth M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451137 , vital:75021 , xlink:href="https://pubs.rsc.org/en/content/articlehtml/2022/nj/d1nj03056f"
- Description: N-Salicylideneaniline (SA) and its derivatives are known to possess chromism upon exposure to external stimuli. Herein, we present mechanochemical synthesis of a series of photo-and thermoresponsive SAderivatives and report on solid-state stabilisation of their tautomeric forms either by change in temperature or by photoirradiation. The influence of UV light on proton transfer between the enol-imine (EI) and keto-amine (KA) forms was investigated at l1 = 254 and l2 = 365 nm. Differential scanning calorimetry (DSC) measurements provided extra information on the thermodynamic relationship between the prototropic tautomers, and their exposition to liquid nitrogen, combined with variable temperature single-crystal X-ray diffraction (VT-SCXRD) and spectroscopic data, ascertained structural reasons for the intrinsic thermo-optical properties of the compounds. A series of structural determinations between 150 and 300 K further shed light on the thermomechanical behaviour exhibited by the thermoresponsive compounds. By virtue of calorimetry we were able to demonstrate proton transfer via the intramolecular ON hydrogen bond over the temperature range 193–453 K. This present work demonstrates the importance of applying complementary analytical techniques and appropriate approaches for understanding the switching behaviour between the EI and KA forms. Furthermore, the assertion that it is predominantly the planarity (j o 251) that determines thermochromaticity is questioned.
- Full Text:
- Date Issued: 2022
Photodegradation of ibuprofen using 5-10-15-20-tetrakis (4-bromophenyl) porphyrin conjugated to graphene quantum dots
- Magaela, N Bridged, Ndlovu, Knowledge S, Tshangana, Charmaine S, Muleia, Adoph A, Mamba, Bhekie B, Nyokong, Tebello, Managa, Muthumuni
- Authors: Magaela, N Bridged , Ndlovu, Knowledge S , Tshangana, Charmaine S , Muleia, Adoph A , Mamba, Bhekie B , Nyokong, Tebello , Managa, Muthumuni
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304819 , vital:58493 , xlink:href="https://doi.org/10.1016/j.optmat.2022.113147"
- Description: Ibuprofen (IBU) is a common anti-inflammatory drug that is consumed by many individuals in the world. As such, analytical studies have detected high concentrations of the drug in many waterbodies, which poses a risk of harmful effects on the environment and public health. The hydroxyl radical technologies, a collective of techniques also known as advanced oxidation processes (AOPs), can be utilized to degrade this emerging pollutant. In this study, the photodegradation of ibuprofen using 5,10,15,20-tetrakis(4-bromophenyl) porphyrin conjugated to graphene quantum dots was investigated using a custom-built photoreactor. Three different concentrations of IBU (200, 300 and 500 μM) were utilized as initial concentrations. The pH of the IBU was varied between acidic (pH 3.0), natural (pH 5.0) and alkaline (pH 9.0) to note the effect on IBU degradation as a function of time. The Highest ФΔ was obtained for InTBrP- GDQs (ФΔ = 0.80), followed by InTBrP (ФΔ = 0.74). The photodegradation efficiency of the TBrP-GQDs and InTBrP-GQDs were determined to be 43.2 and 76.1% respectively.
- Full Text:
- Date Issued: 2022
- Authors: Magaela, N Bridged , Ndlovu, Knowledge S , Tshangana, Charmaine S , Muleia, Adoph A , Mamba, Bhekie B , Nyokong, Tebello , Managa, Muthumuni
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304819 , vital:58493 , xlink:href="https://doi.org/10.1016/j.optmat.2022.113147"
- Description: Ibuprofen (IBU) is a common anti-inflammatory drug that is consumed by many individuals in the world. As such, analytical studies have detected high concentrations of the drug in many waterbodies, which poses a risk of harmful effects on the environment and public health. The hydroxyl radical technologies, a collective of techniques also known as advanced oxidation processes (AOPs), can be utilized to degrade this emerging pollutant. In this study, the photodegradation of ibuprofen using 5,10,15,20-tetrakis(4-bromophenyl) porphyrin conjugated to graphene quantum dots was investigated using a custom-built photoreactor. Three different concentrations of IBU (200, 300 and 500 μM) were utilized as initial concentrations. The pH of the IBU was varied between acidic (pH 3.0), natural (pH 5.0) and alkaline (pH 9.0) to note the effect on IBU degradation as a function of time. The Highest ФΔ was obtained for InTBrP- GDQs (ФΔ = 0.80), followed by InTBrP (ФΔ = 0.74). The photodegradation efficiency of the TBrP-GQDs and InTBrP-GQDs were determined to be 43.2 and 76.1% respectively.
- Full Text:
- Date Issued: 2022
Photodegradation of tetracycline by asymmetrical zinc (II) phthalocyanines conjugated to cobalt tungstate nanoparticles
- Mgidlana, Sithi, Sen, Pinar, Nyokong, Tebello
- Authors: Mgidlana, Sithi , Sen, Pinar , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300233 , vital:57908 , xlink:href="https://doi.org/10.1016/j.molstruc.2022.132938"
- Description: This work focused on syntheses of novel asymmetrically tetra substituted Zn phthalocyanines (ZnPc) each containing a single carboxyl group, with the other substituents bearing alkynyl (complex 1) and fluorine containing groups (complexes 2 and 3). The complexes were conjugated to cobalt tungstate nanoparticles and employed as efficient photocatalysts for degradation of tetracycline in water. ZnPc complexes and their conjugates showed good photophysical and photochemical properties behaviour with complex 1 giving higher triplet and singlet oxygen quantum yields compared to 2 and 3. Complex 1 showed higher activity towards the photodegradation of tetracycline compared to complexes 2 and 3, with higher kobs and initial rates for the former. The photocatalysis obeyed the Langmuir-Hinshelwood kinetic model.
- Full Text:
- Date Issued: 2022
- Authors: Mgidlana, Sithi , Sen, Pinar , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300233 , vital:57908 , xlink:href="https://doi.org/10.1016/j.molstruc.2022.132938"
- Description: This work focused on syntheses of novel asymmetrically tetra substituted Zn phthalocyanines (ZnPc) each containing a single carboxyl group, with the other substituents bearing alkynyl (complex 1) and fluorine containing groups (complexes 2 and 3). The complexes were conjugated to cobalt tungstate nanoparticles and employed as efficient photocatalysts for degradation of tetracycline in water. ZnPc complexes and their conjugates showed good photophysical and photochemical properties behaviour with complex 1 giving higher triplet and singlet oxygen quantum yields compared to 2 and 3. Complex 1 showed higher activity towards the photodegradation of tetracycline compared to complexes 2 and 3, with higher kobs and initial rates for the former. The photocatalysis obeyed the Langmuir-Hinshelwood kinetic model.
- Full Text:
- Date Issued: 2022
Photodynamic activity of novel cationic porphyrins conjugated to graphene quantum dots against Staphylococcus aureus
- Magaela, N Bridged, Makola, Lekgowa C, Managa, Muthumuni, Nyokong, Tebello
- Authors: Magaela, N Bridged , Makola, Lekgowa C , Managa, Muthumuni , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295797 , vital:57379 , xlink:href="https://doi.org/10.1142/S1088424622500316"
- Description: Novel 5-(pyridyl)-10-15-20-tris(4-bromophenyl) porphyrin (complex 1), indium metal derivative (complex 2), and quaternized derivative (complex 3) were synthesized and conjugated to graphene quantum dots (GQDs). The conjugation of the porphyrins to GQDs was through ππ-ππ stacking. Herein, the ππ-ππ stacking approach was used to avoid covalent conjugation which might compromise the intrinsic chemical and physical properties. The photodynamic activities of the proposed nanomaterials were assessed towards Staphylococcus aureus cell obliteration. The photophysical properties of the prepared complexes were also studied prior to the application. Moreover, a decrease in fluorescence lifetimes was observed upon metalation of complex 1. As anticipated, singlet oxygen quantum yield (ΦΔ)ΦΔ) increased notably upon heavy metal (indium) insertion and upon composite formation. Antimicrobial photodynamic therapy comparative studies were done on quaternized and unquaternized indium porphyrins conjugated to GQDs. Complex 3-GQDs exhibited the highest antibacterial activities compared to other complexes, and this was attributed to the high ΦΔΦΔ which plays an imperative role in photodynamic therapy applications.
- Full Text:
- Date Issued: 2022
- Authors: Magaela, N Bridged , Makola, Lekgowa C , Managa, Muthumuni , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295797 , vital:57379 , xlink:href="https://doi.org/10.1142/S1088424622500316"
- Description: Novel 5-(pyridyl)-10-15-20-tris(4-bromophenyl) porphyrin (complex 1), indium metal derivative (complex 2), and quaternized derivative (complex 3) were synthesized and conjugated to graphene quantum dots (GQDs). The conjugation of the porphyrins to GQDs was through ππ-ππ stacking. Herein, the ππ-ππ stacking approach was used to avoid covalent conjugation which might compromise the intrinsic chemical and physical properties. The photodynamic activities of the proposed nanomaterials were assessed towards Staphylococcus aureus cell obliteration. The photophysical properties of the prepared complexes were also studied prior to the application. Moreover, a decrease in fluorescence lifetimes was observed upon metalation of complex 1. As anticipated, singlet oxygen quantum yield (ΦΔ)ΦΔ) increased notably upon heavy metal (indium) insertion and upon composite formation. Antimicrobial photodynamic therapy comparative studies were done on quaternized and unquaternized indium porphyrins conjugated to GQDs. Complex 3-GQDs exhibited the highest antibacterial activities compared to other complexes, and this was attributed to the high ΦΔΦΔ which plays an imperative role in photodynamic therapy applications.
- Full Text:
- Date Issued: 2022
Photodynamic therapy activity of 5, 10, 15-tris (5-bromo-2-thienyl), 20 (phenylcarboxy) porphyrin conjugated to graphene quantum dot against MCF-7 breast cancer cells
- Makola, Lekgowa Collen, Nwahahra, Nnamdi, Managa, Muthumuni, Nyokong, Tebello
- Authors: Makola, Lekgowa Collen , Nwahahra, Nnamdi , Managa, Muthumuni , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300244 , vital:57909 , xlink:href="https://doi.org/10.1080/00958972.2022.2087515"
- Description: A novel 5,10,15-tris(5-bromo-2-thienyl),20(phenylcarboxy)porphyrin and its gallium derivative have been synthesized and fully characterized by various spectroscopic techniques and their respective photophysical and photochemical properties, such as the singlet oxygen quantum yield (ΦΔ), fluorescence quantum yield (ΦF) and triplet lifetime (τT) were determined. The complexes were conjugated to PEI_GQDs resulting is stable conjugates, owing to strong π–π stacking interaction between the PEI_GQDs and the porphyrins. PDT studies were carried out on these nanoconjugates and results obtained indicated they are suitable candidates for further in-depth PDT studies.
- Full Text:
- Date Issued: 2022
- Authors: Makola, Lekgowa Collen , Nwahahra, Nnamdi , Managa, Muthumuni , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300244 , vital:57909 , xlink:href="https://doi.org/10.1080/00958972.2022.2087515"
- Description: A novel 5,10,15-tris(5-bromo-2-thienyl),20(phenylcarboxy)porphyrin and its gallium derivative have been synthesized and fully characterized by various spectroscopic techniques and their respective photophysical and photochemical properties, such as the singlet oxygen quantum yield (ΦΔ), fluorescence quantum yield (ΦF) and triplet lifetime (τT) were determined. The complexes were conjugated to PEI_GQDs resulting is stable conjugates, owing to strong π–π stacking interaction between the PEI_GQDs and the porphyrins. PDT studies were carried out on these nanoconjugates and results obtained indicated they are suitable candidates for further in-depth PDT studies.
- Full Text:
- Date Issued: 2022
Photodynamic therapy characteristics of phthalocyanines in the presence of boron doped detonation nanodiamonds
- Matshitse, Refilwe, Nwaji, Njemuwa, Managa, Muthimuni, Chen, Zhi-Long, Nyokong, Tebello
- Authors: Matshitse, Refilwe , Nwaji, Njemuwa , Managa, Muthimuni , Chen, Zhi-Long , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229921 , vital:49723 , xlink:href="https://doi.org/10.1016/j.pdpdt.2021.102705"
- Description: The synthesis, photophysicochemical and photodynamic therapy (PDT) activities of benzothiazole substituted zinc phthalocyanine (Pc): 1 (asymmetrically substituted and composed of no charges), 2 (asymmetrically substituted and composed of three positive charges), and 3 (symmetrically substituted and composed of four positive charges), are presented. The triplet and singlet oxygen quantum yields were highest for complex 2 showing the importance of asymmetry and charge. The complexes are covalently and non-covalently linked to B doped detonation nanodiamonds (B@DNDs) to yield nanohybrids (B@DNDs-1, B@DNDs-2, B@DNDs-3). The presence of B@DNDs, asymmetry and positive charge resulted in improved PDT with the lowest cell viability being observed for B@DNDs-2 at 5%. The cell viability ranged from 5% to 7% for the nanohybrids compared to 19–26% for Pcs alone.
- Full Text:
- Date Issued: 2022
- Authors: Matshitse, Refilwe , Nwaji, Njemuwa , Managa, Muthimuni , Chen, Zhi-Long , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229921 , vital:49723 , xlink:href="https://doi.org/10.1016/j.pdpdt.2021.102705"
- Description: The synthesis, photophysicochemical and photodynamic therapy (PDT) activities of benzothiazole substituted zinc phthalocyanine (Pc): 1 (asymmetrically substituted and composed of no charges), 2 (asymmetrically substituted and composed of three positive charges), and 3 (symmetrically substituted and composed of four positive charges), are presented. The triplet and singlet oxygen quantum yields were highest for complex 2 showing the importance of asymmetry and charge. The complexes are covalently and non-covalently linked to B doped detonation nanodiamonds (B@DNDs) to yield nanohybrids (B@DNDs-1, B@DNDs-2, B@DNDs-3). The presence of B@DNDs, asymmetry and positive charge resulted in improved PDT with the lowest cell viability being observed for B@DNDs-2 at 5%. The cell viability ranged from 5% to 7% for the nanohybrids compared to 19–26% for Pcs alone.
- Full Text:
- Date Issued: 2022
Phthalocyanine based fabricated exfoliated graphite photoanode for electrodegradation of 4-acetamidophenol under visible light irradiation
- Mpeta, Lekhetho S, Nyokong, Tebello
- Authors: Mpeta, Lekhetho S , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295809 , vital:57380 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114115"
- Description: In this study exfoliated graphite (EG) was prepared from natural graphite flakes and incorporated with zinc phthalocyanine for fabrication of photoanode. The electron transfer capabilities of fabricated photoanode were examined by using cyclic voltammetry, electrochemical impedance spectroscopy and scanning electrochemical microscopy. Electrophotocatalytic degradation of 4-acetamidophenol in 0.1 M Na2SO4 electrolyte was performed. The photoanode with zinc phthalocyanine (EG-ZnPc) displayed better degradation compared to when only exfoliated graphite was used (EG). Furthermore, electrophotocatalytic degradation gave better performance (removal efficiency of 47.76%) than when individual electrochemical degradation and photodegradation techniques were used.
- Full Text:
- Date Issued: 2022
- Authors: Mpeta, Lekhetho S , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295809 , vital:57380 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114115"
- Description: In this study exfoliated graphite (EG) was prepared from natural graphite flakes and incorporated with zinc phthalocyanine for fabrication of photoanode. The electron transfer capabilities of fabricated photoanode were examined by using cyclic voltammetry, electrochemical impedance spectroscopy and scanning electrochemical microscopy. Electrophotocatalytic degradation of 4-acetamidophenol in 0.1 M Na2SO4 electrolyte was performed. The photoanode with zinc phthalocyanine (EG-ZnPc) displayed better degradation compared to when only exfoliated graphite was used (EG). Furthermore, electrophotocatalytic degradation gave better performance (removal efficiency of 47.76%) than when individual electrochemical degradation and photodegradation techniques were used.
- Full Text:
- Date Issued: 2022
Plagiarism and the commodification of knowledge
- Authors: McKenna, Sioux
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426967 , vital:72404 , xlink:href="https://doi.org/10.1007/s10734-022-00926-5"
- Description: Universities have put in place various policies and punishments to manage plagiarism and it is an issue of signifcant interest. This article looks at how plagiarism is discussed in the 55 Higher Education articles between 1982 and June 2022 that make some reference to the term. Many of the articles focused on a police-catch-punish approach and imbued a strong moral charge to the issue. In contrast to such articles were those that presented citation as a complex academic practice that needs to be engaged with educationally. Our understandings of and responses to plagiarism emerge from a number of causal mechanisms but I argue that a key mechanism is the commodifcation of knowledge. Where knowledge is a product to be packaged, bought, and sold, then ownership and attribution become more important than engagement and personal meaning making. Instead of our obsession with a police-catch-punish approach to plagiarism, at a more micro-level, we should be inducting students into the many roles citations serve, and at a macro-level, we should be engaging in considerations of the purposes of a higher education and how we might better enable students to enjoy a transformative relationship to knowledge.
- Full Text:
- Date Issued: 2022
- Authors: McKenna, Sioux
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426967 , vital:72404 , xlink:href="https://doi.org/10.1007/s10734-022-00926-5"
- Description: Universities have put in place various policies and punishments to manage plagiarism and it is an issue of signifcant interest. This article looks at how plagiarism is discussed in the 55 Higher Education articles between 1982 and June 2022 that make some reference to the term. Many of the articles focused on a police-catch-punish approach and imbued a strong moral charge to the issue. In contrast to such articles were those that presented citation as a complex academic practice that needs to be engaged with educationally. Our understandings of and responses to plagiarism emerge from a number of causal mechanisms but I argue that a key mechanism is the commodifcation of knowledge. Where knowledge is a product to be packaged, bought, and sold, then ownership and attribution become more important than engagement and personal meaning making. Instead of our obsession with a police-catch-punish approach to plagiarism, at a more micro-level, we should be inducting students into the many roles citations serve, and at a macro-level, we should be engaging in considerations of the purposes of a higher education and how we might better enable students to enjoy a transformative relationship to knowledge.
- Full Text:
- Date Issued: 2022
Planetary Urgency, Researcher Reflexivity and ESE Research: Questions Arising from an Initial Exploration of Goethean-inspired Phenomenology
- Authors: Olvitt, Lausanne L
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437541 , vital:73392 , ISBN
- Description: Many of the theoretical and methodological frameworks that are currently influential in Environment and Sustainability Education (ESE) research in South Africa foreground interventionist research, activism, causal explanation, critique, social-ecological transformation and decoloniality. These frameworks guide ESE researchers to design, implement and report on research in particular ways, hence influencing how social-ecological phenomena, learning and social change are understood and enacted. In this essay, I present some exploratory perspectives on the relevance and potential contribution of phenomenological approaches to ESE research, especially Goethean inspired observation.
- Full Text:
- Date Issued: 2022
- Authors: Olvitt, Lausanne L
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437541 , vital:73392 , ISBN
- Description: Many of the theoretical and methodological frameworks that are currently influential in Environment and Sustainability Education (ESE) research in South Africa foreground interventionist research, activism, causal explanation, critique, social-ecological transformation and decoloniality. These frameworks guide ESE researchers to design, implement and report on research in particular ways, hence influencing how social-ecological phenomena, learning and social change are understood and enacted. In this essay, I present some exploratory perspectives on the relevance and potential contribution of phenomenological approaches to ESE research, especially Goethean inspired observation.
- Full Text:
- Date Issued: 2022
Postgraduate education in a globalised world
- Authors: Boughey, Chrissie
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434469 , vital:73066 , ISBN 9781991201225 , https://www.google.co.za/books/edition/The_Global_Scholar/KvQ3EAAAQBAJ?hl=enandgbpv=0
- Description: Interest in postgraduate education and the supervision of postgraduate research has developed in recent years, largely as a result of the impact of the so-called ‘knowledge economy’. South Africa’s National Plan 20301 draws on globalised discourses in holding that increases in the number of graduates, particularly at doctoral level, will contribute to economic prosperity because of the potential of postgraduate education to contribute to the processes of reinvention that drive the economic system itself. Even a brief glance at the mission and vision statements of a small sample of universities shows how this idea has been taken up within the higher education sector. In the context of high levels of unemployment, the idea that a postgraduate degree can lead to better work prospects also means that students who might never have considered doing a postgraduate degree previously, have now come forward to study at this level. All this then means that academics are being called upon to take on heavier supervision loads with a diverse array of students.
- Full Text:
- Date Issued: 2022
- Authors: Boughey, Chrissie
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434469 , vital:73066 , ISBN 9781991201225 , https://www.google.co.za/books/edition/The_Global_Scholar/KvQ3EAAAQBAJ?hl=enandgbpv=0
- Description: Interest in postgraduate education and the supervision of postgraduate research has developed in recent years, largely as a result of the impact of the so-called ‘knowledge economy’. South Africa’s National Plan 20301 draws on globalised discourses in holding that increases in the number of graduates, particularly at doctoral level, will contribute to economic prosperity because of the potential of postgraduate education to contribute to the processes of reinvention that drive the economic system itself. Even a brief glance at the mission and vision statements of a small sample of universities shows how this idea has been taken up within the higher education sector. In the context of high levels of unemployment, the idea that a postgraduate degree can lead to better work prospects also means that students who might never have considered doing a postgraduate degree previously, have now come forward to study at this level. All this then means that academics are being called upon to take on heavier supervision loads with a diverse array of students.
- Full Text:
- Date Issued: 2022
Principles of Computer Architecture
- Authors: Machanick, Philip
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439184 , vital:73553 , https://homes.cs.ru.ac.za/philip/Courses/CSHonsArch/HonsArchNotes2022.pdf
- Description: Last week, Control Data ... announced the 6600 system. I understand that in the laboratory developing the system there are only 34 people including the janitor. Of these, 14 are engineers and 4 are programmers... Contrasting this modest effort with our vast development activities, I fail to understand why we have lost our industry leadership position by letting someone else offer the world’s most powerful computer – Thomas Watson Jr., IBM CEO, August 1963 It seems like Mr. Watson has answered his own question – Seymour Cray
- Full Text:
- Date Issued: 2022
- Authors: Machanick, Philip
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439184 , vital:73553 , https://homes.cs.ru.ac.za/philip/Courses/CSHonsArch/HonsArchNotes2022.pdf
- Description: Last week, Control Data ... announced the 6600 system. I understand that in the laboratory developing the system there are only 34 people including the janitor. Of these, 14 are engineers and 4 are programmers... Contrasting this modest effort with our vast development activities, I fail to understand why we have lost our industry leadership position by letting someone else offer the world’s most powerful computer – Thomas Watson Jr., IBM CEO, August 1963 It seems like Mr. Watson has answered his own question – Seymour Cray
- Full Text:
- Date Issued: 2022
Promotion of Catalytic Oxygen Reduction Reactions
- Wei, Yuqin, Zhao, Long, Yuan, Rui, Xue, Zhaoli, Mack, John, Chivumba, Choonzo, Nyokong, Tebello, Zhang, Jianming
- Authors: Wei, Yuqin , Zhao, Long , Yuan, Rui , Xue, Zhaoli , Mack, John , Chivumba, Choonzo , Nyokong, Tebello , Zhang, Jianming
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300347 , vital:57919 , xlink:href="https://doi.org/10.1021/acs.inorgchem.2c01591"
- Description: Three ABAB-type cobalt meso-tetraarylporphyrins with fluorine (F-CoPor), acetic acid (AC-CoPor), and cyanoacetic acid (CN-CoPor) groups at the para-positions of phenyl rings at the 10,20-positions are synthesized and evaluated as catalysts for oxygen reduction reactions (ORRs). In density functional theory calculations, the frontier molecular orbitals of these complexes were found to be stabilized relative to model complexes with electron-withdrawing atoms or moieties on the meso-aryl rings. Electrochemical measurements suggest that electrodes with CN-CoPor (CN-CoPor/C) exhibit the most positive ORR potential values and the highest limiting current density in both acidic and alkali electrolytes, while the F-CoPor/C electrocatalyst exhibits extremely low ORR performance. The electron transfer numbers for the electrocatalysts are more than 3.0, indicating that a mixture of 2- and 4-electron transfer pathways occurs. The results demonstrate that coupling the hydrogen bonding properties and electron-withdrawing abilities through rational design of the substituent at the meso-position is an efficient way to modify the ORR performance.
- Full Text:
- Date Issued: 2022
- Authors: Wei, Yuqin , Zhao, Long , Yuan, Rui , Xue, Zhaoli , Mack, John , Chivumba, Choonzo , Nyokong, Tebello , Zhang, Jianming
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300347 , vital:57919 , xlink:href="https://doi.org/10.1021/acs.inorgchem.2c01591"
- Description: Three ABAB-type cobalt meso-tetraarylporphyrins with fluorine (F-CoPor), acetic acid (AC-CoPor), and cyanoacetic acid (CN-CoPor) groups at the para-positions of phenyl rings at the 10,20-positions are synthesized and evaluated as catalysts for oxygen reduction reactions (ORRs). In density functional theory calculations, the frontier molecular orbitals of these complexes were found to be stabilized relative to model complexes with electron-withdrawing atoms or moieties on the meso-aryl rings. Electrochemical measurements suggest that electrodes with CN-CoPor (CN-CoPor/C) exhibit the most positive ORR potential values and the highest limiting current density in both acidic and alkali electrolytes, while the F-CoPor/C electrocatalyst exhibits extremely low ORR performance. The electron transfer numbers for the electrocatalysts are more than 3.0, indicating that a mixture of 2- and 4-electron transfer pathways occurs. The results demonstrate that coupling the hydrogen bonding properties and electron-withdrawing abilities through rational design of the substituent at the meso-position is an efficient way to modify the ORR performance.
- Full Text:
- Date Issued: 2022
Reaction of Perrhenate with Phthalocyanine Derivatives in the Presence of Reducing Agents and Rhenium Oxide Nanoparticles in Biomedical Applications
- Ntsimango, Songeziwe, Gandidzanwa, Sendibitiyosi, Joseph, Sinelizwi V, Hosten, Eric C, Randall, Marvin, Edkins, Adrienne L, Khene, Samson M, Mashazi, Philani N, Nyokong, Tebello, Abrahams, Abubak’r, Tshentu, Zenixole R
- Authors: Ntsimango, Songeziwe , Gandidzanwa, Sendibitiyosi , Joseph, Sinelizwi V , Hosten, Eric C , Randall, Marvin , Edkins, Adrienne L , Khene, Samson M , Mashazi, Philani N , Nyokong, Tebello , Abrahams, Abubak’r , Tshentu, Zenixole R
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300257 , vital:57910 , xlink:href="https://doi.org/10.1002/open.202200037"
- Description: A novel alternative route to access rhenium(V)−phthalocyanine complexes through direct metalation of metal-free phthalocyanines (H2Pcs) with a rhenium(VII) salt in the presence of various two-electron reducing agents is presented. Direct ion metalation of tetraamino- or tetranitrophthalocyanine with perrhenate (ReO4−) in the presence of triphenylphosphine led to oxidative decomposition of the H2Pcs, giving their respective phthalonitriles. Conversely, treatment of H2Pcs with ReO4− employing sodium metabisulfite yielded the desired ReVO−Pc complex. Finally, reaction of H2Pcs with ReO4− and NaBH4 as reducing agent led to the formation of rhenium oxide (RexOy) nanoparticles (NPs). The NP synthesis was optimised, and the RexOy NPs were capped with folic acid (FA) conjugated with tetraaminophthalocyanine (TAPc) to enhance their cancer cell targeting ability. The cytotoxicity profile of the resultant RexOy−TAPc−FA NPs was assessed and found to be greater than 80 % viability in four cell lines, namely, MDA−MB-231, HCC7, HCC1806 and HEK293T. Non-cytotoxic concentrations were determined and employed in cancer cell localization studies. The particle size effect on localization of NPs was also investigated using confocal fluorescence and transmission electron microscopy. The smaller NPs (≈10 nm) were found to exhibit stronger fluorescence properties than the ≈50 nm NPs and exhibited better cell localization ability than the ≈50 nm NPs.
- Full Text:
- Date Issued: 2022
- Authors: Ntsimango, Songeziwe , Gandidzanwa, Sendibitiyosi , Joseph, Sinelizwi V , Hosten, Eric C , Randall, Marvin , Edkins, Adrienne L , Khene, Samson M , Mashazi, Philani N , Nyokong, Tebello , Abrahams, Abubak’r , Tshentu, Zenixole R
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300257 , vital:57910 , xlink:href="https://doi.org/10.1002/open.202200037"
- Description: A novel alternative route to access rhenium(V)−phthalocyanine complexes through direct metalation of metal-free phthalocyanines (H2Pcs) with a rhenium(VII) salt in the presence of various two-electron reducing agents is presented. Direct ion metalation of tetraamino- or tetranitrophthalocyanine with perrhenate (ReO4−) in the presence of triphenylphosphine led to oxidative decomposition of the H2Pcs, giving their respective phthalonitriles. Conversely, treatment of H2Pcs with ReO4− employing sodium metabisulfite yielded the desired ReVO−Pc complex. Finally, reaction of H2Pcs with ReO4− and NaBH4 as reducing agent led to the formation of rhenium oxide (RexOy) nanoparticles (NPs). The NP synthesis was optimised, and the RexOy NPs were capped with folic acid (FA) conjugated with tetraaminophthalocyanine (TAPc) to enhance their cancer cell targeting ability. The cytotoxicity profile of the resultant RexOy−TAPc−FA NPs was assessed and found to be greater than 80 % viability in four cell lines, namely, MDA−MB-231, HCC7, HCC1806 and HEK293T. Non-cytotoxic concentrations were determined and employed in cancer cell localization studies. The particle size effect on localization of NPs was also investigated using confocal fluorescence and transmission electron microscopy. The smaller NPs (≈10 nm) were found to exhibit stronger fluorescence properties than the ≈50 nm NPs and exhibited better cell localization ability than the ≈50 nm NPs.
- Full Text:
- Date Issued: 2022
Refining youth sexualities empowerment programmes: The development of the Masizixhobise Toolkit based on a critical sexual and reproductive citizenship framework
- Macleod, Catriona I, Moore, Sarah-Ann
- Authors: Macleod, Catriona I , Moore, Sarah-Ann
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434158 , vital:73035 , ISBN 9781003139782 , https://www.taylorfrancis.com/chapters/edit/10.4324/9781003139782-15/refining-youth-sexualities-empowerment-programmes-catriona-ida-macleod-sarah-moore
- Description: Youth sexualities programmes frequently focus on empowering young people in relation to sexual decision-making and interactions. Within these programmes, however, empowerment is mostly equated with the individualised concepts of self-efficacy and agency to the exclusion of interpersonal and social (i.e. collective) components. Resultantly, the social justice aspects of empowerment may be overlooked. Noting this, some researchers have argued for the adoption of a broader, integrative conceptualisation of empowerment. Macleod’s and Vincent’s critical sexual and reproductive citizenship (CSRC) framework provides such a conceptualisation. This framework draws from feminist re-workings of the principles of citizenship and applies these to understandings of CSRC. Based on this framework, key issues for consideration in programmes are: sexual and reproductive citizenship as status and practice; situated agency; differentiated universalism; the interweaving of the private and public; and the politics of recognition, redistribution and reparation. This chapter discusses the development of a programme refinement toolkit based on a CSRC framework, named the Masizixhobise Toolkit; how the elements outlined above were operationalised into questions; an illustrative example; and the partnership formed with a youth empowerment non-governmental organisation in developing the toolkit.
- Full Text:
- Date Issued: 2022
- Authors: Macleod, Catriona I , Moore, Sarah-Ann
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434158 , vital:73035 , ISBN 9781003139782 , https://www.taylorfrancis.com/chapters/edit/10.4324/9781003139782-15/refining-youth-sexualities-empowerment-programmes-catriona-ida-macleod-sarah-moore
- Description: Youth sexualities programmes frequently focus on empowering young people in relation to sexual decision-making and interactions. Within these programmes, however, empowerment is mostly equated with the individualised concepts of self-efficacy and agency to the exclusion of interpersonal and social (i.e. collective) components. Resultantly, the social justice aspects of empowerment may be overlooked. Noting this, some researchers have argued for the adoption of a broader, integrative conceptualisation of empowerment. Macleod’s and Vincent’s critical sexual and reproductive citizenship (CSRC) framework provides such a conceptualisation. This framework draws from feminist re-workings of the principles of citizenship and applies these to understandings of CSRC. Based on this framework, key issues for consideration in programmes are: sexual and reproductive citizenship as status and practice; situated agency; differentiated universalism; the interweaving of the private and public; and the politics of recognition, redistribution and reparation. This chapter discusses the development of a programme refinement toolkit based on a CSRC framework, named the Masizixhobise Toolkit; how the elements outlined above were operationalised into questions; an illustrative example; and the partnership formed with a youth empowerment non-governmental organisation in developing the toolkit.
- Full Text:
- Date Issued: 2022