Symmetry effect of cobalt phthalocyanines on the aluminium corrosion inhibition in hydrochloric acid
- Nnaji, Nnaemeka, Sen, Pinar, Nyokong, Tebello
- Authors: Nnaji, Nnaemeka , Sen, Pinar , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/231323 , vital:49877 , xlink:href="https://doi.org/10.1016/j.matlet.2021.130892"
- Description: The aluminium corrosion retardation potentials of phthalocyanine-based dyes, cobalt (II) 2,9,16-tris(4-(tert-butyl)phenoxy)-23-(pyridin-4-yloxy)phthalocyanine (D1) and cobalt (II) 2,9,16,24-tetrakis(4-(tert-butyl)phenoxy)phthalocyanine (D2) in 1 M hydrochloric acid were evaluated. Results from potentiodynamic polarization measurements show that inhibition efficiency increased with inhibitor concentration at 28 °C with values of 91.9 % and 87.0 % values respectively for D1 and D2 at 10 μM.
- Full Text:
- Date Issued: 2022
Symmetry effect of cobalt phthalocyanines on the aluminium corrosion inhibition in hydrochloric acid
- Authors: Nnaji, Nnaemeka , Sen, Pinar , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/231323 , vital:49877 , xlink:href="https://doi.org/10.1016/j.matlet.2021.130892"
- Description: The aluminium corrosion retardation potentials of phthalocyanine-based dyes, cobalt (II) 2,9,16-tris(4-(tert-butyl)phenoxy)-23-(pyridin-4-yloxy)phthalocyanine (D1) and cobalt (II) 2,9,16,24-tetrakis(4-(tert-butyl)phenoxy)phthalocyanine (D2) in 1 M hydrochloric acid were evaluated. Results from potentiodynamic polarization measurements show that inhibition efficiency increased with inhibitor concentration at 28 °C with values of 91.9 % and 87.0 % values respectively for D1 and D2 at 10 μM.
- Full Text:
- Date Issued: 2022
Indium phthalocyanines
- Pinar, Sen, Mack, John, Nyokong, Tebello
- Authors: Pinar, Sen , Mack, John , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229998 , vital:49731 , xlink:href="https://doi.org/10.1016/j.molstruc.2021.131850"
- Description: In this study, the photodynamic antimicrobial activities of a series of new tetra-substituted indium phthalocyanine (InPc) complexes are assessed. An aldehyde substituted complex (2) was initially prepared, which was converted through a condensatioreaction to an imine-pyrrolidine substituted complex (3), which in turn was quaternized to form a tetracationic species (4). Favorable photophysicochemical properties were obtained by incorporating a heavy In(III) ion into the central cavity. Aggregation studies revealed that 2–4 remain non-aggregated in DMSO at concentration below 25 µM. The photodeactivation of S.aureus and E.coli was studied. Log reduction values > 9.0 were obtained for cationic InPc 4 after 30 min of incubation and exposure to light for 75 min.
- Full Text:
- Date Issued: 2022
- Authors: Pinar, Sen , Mack, John , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229998 , vital:49731 , xlink:href="https://doi.org/10.1016/j.molstruc.2021.131850"
- Description: In this study, the photodynamic antimicrobial activities of a series of new tetra-substituted indium phthalocyanine (InPc) complexes are assessed. An aldehyde substituted complex (2) was initially prepared, which was converted through a condensatioreaction to an imine-pyrrolidine substituted complex (3), which in turn was quaternized to form a tetracationic species (4). Favorable photophysicochemical properties were obtained by incorporating a heavy In(III) ion into the central cavity. Aggregation studies revealed that 2–4 remain non-aggregated in DMSO at concentration below 25 µM. The photodeactivation of S.aureus and E.coli was studied. Log reduction values > 9.0 were obtained for cationic InPc 4 after 30 min of incubation and exposure to light for 75 min.
- Full Text:
- Date Issued: 2022
Ultrasensitive detection of prostate-specific antigen using glucose-encapsulated nanoliposomes anti-PSA polyclonal antibody as detection nanobioprobes
- Mwanza, Daniel, Mfamela, Nololo, Adeniyi, Omotayo, Nyokong, Tebello, Mashazi, Philani N
- Authors: Mwanza, Daniel , Mfamela, Nololo , Adeniyi, Omotayo , Nyokong, Tebello , Mashazi, Philani N
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300268 , vital:57911 , xlink:href="https://doi.org/10.1016/j.talanta.2022.123483"
- Description: In this work, the preparation of glucose encapsulating nanoliposomes was achieved using two different lipid formulations, labelled as F1 and F2. Both formulations contained phosphatidylcholine (PC), oleylamido-4-butanoic acid (OABA) and in addition, F1 had cholesterol (CHO) while F2 contained cholesteroyl hemisussinate (CHEMS). These formulations were studied for their pH sensitivity and controlled release of encapsulated glucose for indirect detection of prostate-specific antigen (PSA) using sandwich immunoassay. As a signal generator, encapsulated glucose in nanoliposomes was quantified directly using the personal glucose meter (PGM) and colorimetrically using peroxidase property of horseradish peroxidase (HRP) enzyme and Pd|PdO as nanozymes. Controlled release of the encapsulated glucose was achieved using the pH effect or Triton-X 100 as a surfactant to destabilize the liposomal structure. The F2 formulation showed maximum controlled release at acidic phosphate buffer saline (PBS, pH 5.0). The concentration of encapsulated glucose was found to be high in F2 formulation and these were applied for the indirect detection of PSA. The limit of detection (LOD) values for PSA were found to be 53 fg mL−1, 64 fg mL−1 and 10 fg mL−1 when HRP, Pd|PdO and PGM were respectively used. The detection signal was linear over a wide concentration range for PSA including the clinical range of 4–10 ng mL−1. The HRP system showed low LOD value when compared with Pd|PdO nanozymes. PGM system gave lowest LOD values owing to the sensitivity of the system towards glucose. Pd|PdO nanozyme system showed good stability over a wide temperature up to 80 °C. PGM system required less reaction time (2 min), low reagents and results were readily generated in digital format.
- Full Text:
- Date Issued: 2022
- Authors: Mwanza, Daniel , Mfamela, Nololo , Adeniyi, Omotayo , Nyokong, Tebello , Mashazi, Philani N
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300268 , vital:57911 , xlink:href="https://doi.org/10.1016/j.talanta.2022.123483"
- Description: In this work, the preparation of glucose encapsulating nanoliposomes was achieved using two different lipid formulations, labelled as F1 and F2. Both formulations contained phosphatidylcholine (PC), oleylamido-4-butanoic acid (OABA) and in addition, F1 had cholesterol (CHO) while F2 contained cholesteroyl hemisussinate (CHEMS). These formulations were studied for their pH sensitivity and controlled release of encapsulated glucose for indirect detection of prostate-specific antigen (PSA) using sandwich immunoassay. As a signal generator, encapsulated glucose in nanoliposomes was quantified directly using the personal glucose meter (PGM) and colorimetrically using peroxidase property of horseradish peroxidase (HRP) enzyme and Pd|PdO as nanozymes. Controlled release of the encapsulated glucose was achieved using the pH effect or Triton-X 100 as a surfactant to destabilize the liposomal structure. The F2 formulation showed maximum controlled release at acidic phosphate buffer saline (PBS, pH 5.0). The concentration of encapsulated glucose was found to be high in F2 formulation and these were applied for the indirect detection of PSA. The limit of detection (LOD) values for PSA were found to be 53 fg mL−1, 64 fg mL−1 and 10 fg mL−1 when HRP, Pd|PdO and PGM were respectively used. The detection signal was linear over a wide concentration range for PSA including the clinical range of 4–10 ng mL−1. The HRP system showed low LOD value when compared with Pd|PdO nanozymes. PGM system gave lowest LOD values owing to the sensitivity of the system towards glucose. Pd|PdO nanozyme system showed good stability over a wide temperature up to 80 °C. PGM system required less reaction time (2 min), low reagents and results were readily generated in digital format.
- 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
Double stimulation and transformative agency for leadership development of school learners in Southern Africa
- Authors: Grant, Carolyn
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281035 , vital:55685 , xlink:href="https://doi.org/10.1080/14681366.2020.1805495"
- Description: Learners, because of their minor status, are a virtual absence in everyday school leadership work, particularly on the African continent. School leadership, therefore, continues to be misconceived as an adult phenomenon. Framed by Cultural Historical Activity Theory, this paper reports on a Southern African Higher Education studythat engages with the Vygotskian principle of ‘double stimulation’ and its relationship to transformative agency in the context of a school-based learner leadership development initiative. One school change project was purposively selected as the case, and data were drawn from a postgraduate student research report and self-reflective journal. Drawing on the Sannino model of double stimulation, the paper explores the phases of double stimulation as well as instances of transformative agency evident in the data, and speculates about the relationship between double stimulation and transformative agency in the leadership development of learners.
- Full Text:
- Date Issued: 2022
- Authors: Grant, Carolyn
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281035 , vital:55685 , xlink:href="https://doi.org/10.1080/14681366.2020.1805495"
- Description: Learners, because of their minor status, are a virtual absence in everyday school leadership work, particularly on the African continent. School leadership, therefore, continues to be misconceived as an adult phenomenon. Framed by Cultural Historical Activity Theory, this paper reports on a Southern African Higher Education studythat engages with the Vygotskian principle of ‘double stimulation’ and its relationship to transformative agency in the context of a school-based learner leadership development initiative. One school change project was purposively selected as the case, and data were drawn from a postgraduate student research report and self-reflective journal. Drawing on the Sannino model of double stimulation, the paper explores the phases of double stimulation as well as instances of transformative agency evident in the data, and speculates about the relationship between double stimulation and transformative agency in the leadership development of learners.
- Full Text:
- Date Issued: 2022
A Change Project story: learning and caring for South Africa’s rivers
- Authors: Chetty, Preven
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391060 , vital:68613 , xlink:href="https://eeasa.org.za/wp-content/uploads/2023/02/Final-EEASA-Bulletin-20212022-Final.pdf"
- Description: Water quality and scarcity is a major concern in Southern Africa and globally especially as the threat of climate change looms even closer. The current drought in South Africa and worsening rainfall has exposed the brittle nature of this country’s resilience to water shortages. Compounded to this is the fact that most rivers in South Africa are not adequately cared for and are under tremendous strain. Everyone who depends on these rivers whether directly or indirectly will soon be entering a new era where water will no longer be a ubiquitous commodity.
- Full Text:
- Date Issued: 2022
- Authors: Chetty, Preven
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391060 , vital:68613 , xlink:href="https://eeasa.org.za/wp-content/uploads/2023/02/Final-EEASA-Bulletin-20212022-Final.pdf"
- Description: Water quality and scarcity is a major concern in Southern Africa and globally especially as the threat of climate change looms even closer. The current drought in South Africa and worsening rainfall has exposed the brittle nature of this country’s resilience to water shortages. Compounded to this is the fact that most rivers in South Africa are not adequately cared for and are under tremendous strain. Everyone who depends on these rivers whether directly or indirectly will soon be entering a new era where water will no longer be a ubiquitous commodity.
- Full Text:
- Date Issued: 2022
Working in poverty: Informal employment of household gardeners in Eastern Cape towns, South Africa
- King, A, Shackleton, Charlie M
- Authors: King, A , Shackleton, Charlie M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/401398 , vital:69731 , xlink:href="https://doi.org/10.1080/0376835X.2021.1940867"
- Description: In South Africa there has been relatively little consideration of the informal employment offered to domestic household workers and gardeners. Here we report on the number and profile of gardeners employed by private households and the wage and satisfaction rates in 12 towns of the Eastern Cape. Over 98% of the informal gardeners were male, middle-aged and with limited formal schooling. Approximately 58% of middle and upper income households employed a gardener, at a mean daily rate of R112.20 in 2019. This equated to 13 170 gardeners earning a total wage bill of R139 million p.a. across the 12 towns, which scales up to 0.7–1 million informal gardeners nationally earning approximately R10–14 billion per year. However, daily remuneration was insufficient to cover basic needs, and slightly more than half of the gardeners would prefer a different job, indicating the survivalist nature of the sector.
- Full Text:
- Date Issued: 2022
- Authors: King, A , Shackleton, Charlie M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/401398 , vital:69731 , xlink:href="https://doi.org/10.1080/0376835X.2021.1940867"
- Description: In South Africa there has been relatively little consideration of the informal employment offered to domestic household workers and gardeners. Here we report on the number and profile of gardeners employed by private households and the wage and satisfaction rates in 12 towns of the Eastern Cape. Over 98% of the informal gardeners were male, middle-aged and with limited formal schooling. Approximately 58% of middle and upper income households employed a gardener, at a mean daily rate of R112.20 in 2019. This equated to 13 170 gardeners earning a total wage bill of R139 million p.a. across the 12 towns, which scales up to 0.7–1 million informal gardeners nationally earning approximately R10–14 billion per year. However, daily remuneration was insufficient to cover basic needs, and slightly more than half of the gardeners would prefer a different job, indicating the survivalist nature of the sector.
- Full Text:
- Date Issued: 2022
The emergence of isiZulu in Skeem Saam (2011)
- Authors: Aiseng, Kealeboga
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/277956 , vital:55335 , xlink:href="https://doi.org/10.1080/13504630.2022.2063115"
- Description: This study aims to investigate how an ecological understanding of polyglossia is used in the South African Broadcasting Corporation’s (SABC) television channel, SABC 1 to maintain and create ethnolinguistic dominance. Key arguments this study will make are: (1) polyglossia is a language ideology masquerading as ethnolinguistic pluralism, (2) there is a loss of ethnolinguistic pluralism in SABC 1 because of the polyglot culture and its transmissions, (3) isiZulu is emerging as a language and cultural flare of the channel. This paper concluded that isiZulu’s presence is rising in a soap initially meant to be a Sepedi show. And this has negative consequences for language equality in the SABC.
- Full Text:
- Date Issued: 2022
- Authors: Aiseng, Kealeboga
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/277956 , vital:55335 , xlink:href="https://doi.org/10.1080/13504630.2022.2063115"
- Description: This study aims to investigate how an ecological understanding of polyglossia is used in the South African Broadcasting Corporation’s (SABC) television channel, SABC 1 to maintain and create ethnolinguistic dominance. Key arguments this study will make are: (1) polyglossia is a language ideology masquerading as ethnolinguistic pluralism, (2) there is a loss of ethnolinguistic pluralism in SABC 1 because of the polyglot culture and its transmissions, (3) isiZulu is emerging as a language and cultural flare of the channel. This paper concluded that isiZulu’s presence is rising in a soap initially meant to be a Sepedi show. And this has negative consequences for language equality in the SABC.
- 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
Is green space associated with reduced crime? A national-scale study from the Global South
- Venter, Zander S, Shackleton, Charlie M, Faull, Andrew, Lancaster, Lizette, Breetzke, Gregory, Edelstein, Ian
- Authors: Venter, Zander S , Shackleton, Charlie M , Faull, Andrew , Lancaster, Lizette , Breetzke, Gregory , Edelstein, Ian
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402340 , vital:69843 , xlink:href="https://doi.org/10.1016/j.scitotenv.2022.154005"
- Description: Assumptions about the link between green space and crime mitigation are informed by literature that overwhelmingly originates in the Global North. Little is known about the association between green spaces and crime in the Global South. We utilized 10 years of precinct-level crime statistics (n = 1152) over South Africa, a global crime hotspot, to test the hypothesis that green space is associated with reduced crime rates. We found that, after controlling for a number of socio-demographic confounders (unemployment, income, age, education, land use and population density), for every 1% increase in total green space there is a 1.2% (0.7 to 1.7%; 95% confidence interval) decrease in violent crime, and 1.3% (0.8 to 1.8%) decrease in property crime, with no effect on sexual crimes. However, the direction of the association changed for property crimes when exploring the effect of green space characteristics including tree cover and park accessibility. Property crimes increase by 0.4% (0.1 to 0.7%) with a percentage increase in tree cover, and by 0.9% (0.5 to 1.3%) with every kilometer increase in proximity to a public park. Further research, including experimental studies, is needed to better isolate causal mechanisms behind crime-green space associations, especially considering that green space may map to race and income inequality and that there may be more crime reporting in affluent areas. Nevertheless, our results provide a complementary contribution to the evidence from the Global North, highlighting the need for more nuanced definitions of green space and its characteristics when considering links to crime. When viewed in light of the broader suite of ecosystem services provided by green space, our results support urban greening as a major strategy towards achieving just and sustainable cities and towns.
- Full Text:
- Date Issued: 2022
- Authors: Venter, Zander S , Shackleton, Charlie M , Faull, Andrew , Lancaster, Lizette , Breetzke, Gregory , Edelstein, Ian
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402340 , vital:69843 , xlink:href="https://doi.org/10.1016/j.scitotenv.2022.154005"
- Description: Assumptions about the link between green space and crime mitigation are informed by literature that overwhelmingly originates in the Global North. Little is known about the association between green spaces and crime in the Global South. We utilized 10 years of precinct-level crime statistics (n = 1152) over South Africa, a global crime hotspot, to test the hypothesis that green space is associated with reduced crime rates. We found that, after controlling for a number of socio-demographic confounders (unemployment, income, age, education, land use and population density), for every 1% increase in total green space there is a 1.2% (0.7 to 1.7%; 95% confidence interval) decrease in violent crime, and 1.3% (0.8 to 1.8%) decrease in property crime, with no effect on sexual crimes. However, the direction of the association changed for property crimes when exploring the effect of green space characteristics including tree cover and park accessibility. Property crimes increase by 0.4% (0.1 to 0.7%) with a percentage increase in tree cover, and by 0.9% (0.5 to 1.3%) with every kilometer increase in proximity to a public park. Further research, including experimental studies, is needed to better isolate causal mechanisms behind crime-green space associations, especially considering that green space may map to race and income inequality and that there may be more crime reporting in affluent areas. Nevertheless, our results provide a complementary contribution to the evidence from the Global North, highlighting the need for more nuanced definitions of green space and its characteristics when considering links to crime. When viewed in light of the broader suite of ecosystem services provided by green space, our results support urban greening as a major strategy towards achieving just and sustainable cities and towns.
- Full Text:
- Date Issued: 2022
Application of gold and palladium nanoparticles supported on polymelamine microspheres in the oxidation of 1-phenylethanol and some other phenyl substituted alcohols
- Storm, Ené, Maggott, Emile D, Mashazi, Philani N, Nyokong, Tebello, Malgas-Enus, Rehana, Mapolie, Selwyn F
- Authors: Storm, Ené , Maggott, Emile D , Mashazi, Philani N , Nyokong, Tebello , Malgas-Enus, Rehana , Mapolie, Selwyn F
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/299824 , vital:57858 , xlink:href="https://doi.org/10.1016/j.mcat.2022.112456"
- Description: Melamine formaldehyde and melamine resorcinol formaldehyde microspheres were decorated with Au and Pd nanoparticles and applied as heterogeneous catalysts in the oxidation of 1-phenylethanol. The catalysts showed similar activities irrespective of the support employed. Moderate conversion activities of 48–50% were achieved when using acetonitrile as solvent; however, when employing water as solvent, the supported catalysts formed a three-phase, emulsion system which facilitated the catalytic conversion of 1-phenylethanol to acetophenone at much higher conversions of around 83%. The oxidant, TBHP, decomposed rapidly in acetonitrile, whilst it remained stable in aqueous solution, leading to the enhanced activities observed when using water as solvent. These systems also proved to be recyclable for up to five cycles, with only slight loss of activity observed; this can be attributed to the physical loss of catalyst during the workup procedure conducted between each cycle.
- Full Text:
- Date Issued: 2022
- Authors: Storm, Ené , Maggott, Emile D , Mashazi, Philani N , Nyokong, Tebello , Malgas-Enus, Rehana , Mapolie, Selwyn F
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/299824 , vital:57858 , xlink:href="https://doi.org/10.1016/j.mcat.2022.112456"
- Description: Melamine formaldehyde and melamine resorcinol formaldehyde microspheres were decorated with Au and Pd nanoparticles and applied as heterogeneous catalysts in the oxidation of 1-phenylethanol. The catalysts showed similar activities irrespective of the support employed. Moderate conversion activities of 48–50% were achieved when using acetonitrile as solvent; however, when employing water as solvent, the supported catalysts formed a three-phase, emulsion system which facilitated the catalytic conversion of 1-phenylethanol to acetophenone at much higher conversions of around 83%. The oxidant, TBHP, decomposed rapidly in acetonitrile, whilst it remained stable in aqueous solution, leading to the enhanced activities observed when using water as solvent. These systems also proved to be recyclable for up to five cycles, with only slight loss of activity observed; this can be attributed to the physical loss of catalyst during the workup procedure conducted between each cycle.
- Full Text:
- Date Issued: 2022
Trees stocks in domestic gardens and willingness to participate in tree planting initiatives in low-cost housing areas of the Eastern Cape, South Africa
- Gwedla, Nanamhla, Shackleton, Charlie, Olvitt, Lausanne L
- Authors: Gwedla, Nanamhla , Shackleton, Charlie , Olvitt, Lausanne L
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/372825 , vital:66626 , xlink:href="https://doi.org/10.1016/j.ufug.2022.127484"
- Description: Increasing human populations and rapid urbanization in sub-Saharan Africa have prompted the development and maintenance of urban green infrastructure, including urban trees for sustainability, human wellbeing, liveability and climate resilience. However, there are still insufficient amounts and large inequities in the distribution of trees between and within towns and cities of the Global North and South. In South Africa, urban green space planning and planting are encoded in several policies at national level. However, these policies are rarely translated into specific guides, standards or actions, and consequently disparities in urban trees and green space distribution persist. This study assessed the prevalence of urban trees in domestic gardens in low-cost housing areas (LCHAs) of eight small to medium-sized towns in the Eastern Cape province of South Africa and examined residents’ perceptions in this regard. This was done via surveys with 800 households in old and recently developed LCHAs. The results revealed that most households (52 %) had at least one tree in their yard, with more households in the older neighbourhoods (60 %) reporting having trees than in the newer ones (44 %). Most of the trees (66 %) had been deliberately planted as opposed to natural regeneration. Experience of formal urban tree planting programs was low, but 75 % of residents expressed willingness to participate in the future, preferably in tree planting and maintenance. Urban green spaces and trees cannot be an afterthought in the development of sustainable human settlements, and municipal plans should reflect tangible commitments in this regard. Meeting goals for greener LCHAs requires the involvement of local residents, and for municipal authorities to be receptive to the wishes of residents and willingness to green their residential areas.
- Full Text:
- Date Issued: 2022
- Authors: Gwedla, Nanamhla , Shackleton, Charlie , Olvitt, Lausanne L
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/372825 , vital:66626 , xlink:href="https://doi.org/10.1016/j.ufug.2022.127484"
- Description: Increasing human populations and rapid urbanization in sub-Saharan Africa have prompted the development and maintenance of urban green infrastructure, including urban trees for sustainability, human wellbeing, liveability and climate resilience. However, there are still insufficient amounts and large inequities in the distribution of trees between and within towns and cities of the Global North and South. In South Africa, urban green space planning and planting are encoded in several policies at national level. However, these policies are rarely translated into specific guides, standards or actions, and consequently disparities in urban trees and green space distribution persist. This study assessed the prevalence of urban trees in domestic gardens in low-cost housing areas (LCHAs) of eight small to medium-sized towns in the Eastern Cape province of South Africa and examined residents’ perceptions in this regard. This was done via surveys with 800 households in old and recently developed LCHAs. The results revealed that most households (52 %) had at least one tree in their yard, with more households in the older neighbourhoods (60 %) reporting having trees than in the newer ones (44 %). Most of the trees (66 %) had been deliberately planted as opposed to natural regeneration. Experience of formal urban tree planting programs was low, but 75 % of residents expressed willingness to participate in the future, preferably in tree planting and maintenance. Urban green spaces and trees cannot be an afterthought in the development of sustainable human settlements, and municipal plans should reflect tangible commitments in this regard. Meeting goals for greener LCHAs requires the involvement of local residents, and for municipal authorities to be receptive to the wishes of residents and willingness to green their residential areas.
- Full Text:
- Date Issued: 2022
The effect of charge on Zn tetra morpholine porphyrin conjugated to folic acid-nitrogen doped graphene quantum dots for photodynamic therapy studies
- Magaela, N Bridged, Matshitse, Refilwe, Nyokong, Tebello
- Authors: Magaela, N Bridged , Matshitse, Refilwe , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295840 , vital:57383 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.102898"
- Description: Zinc tetra morpholine porphyrin (complex 2), and its quaternized derivative (complex 3) were synthesized and conjugated to folic acid decorated nitrogen doped graphene quantum dots (FA-NGQDs) through π−π stacking to study their photodynamic therapy (PDT) efficacy. Photophysiochemical properties of complexes 2, 3, and their conjugates (2-FA-NGQDs, 3-FA-NGQDs) were studied. It was found that complex 3 had higher ϕΔ of 0.56 compared to complex 2 with ϕΔ of 0.24, and respective composites: 3-FA-NGQDs had higher ϕΔ compared to 2-FA-NGQDs. The PDT studies were conducted for nanoparticles (FA-NGQDs), complexes (2, 3), and respective composites (2-FA-NGQDs, and 3-FA-NGQDs) using MCF-7 breast cancer cell. Dark toxicity of all compounds was above 90% which is negligible. At a highest concentration of 40 µg/mL, 3-FA-NGQDs gave the lowest cell viability of 28% compared to all other conjugates and porphyrins alone.
- Full Text:
- Date Issued: 2022
- Authors: Magaela, N Bridged , Matshitse, Refilwe , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295840 , vital:57383 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.102898"
- Description: Zinc tetra morpholine porphyrin (complex 2), and its quaternized derivative (complex 3) were synthesized and conjugated to folic acid decorated nitrogen doped graphene quantum dots (FA-NGQDs) through π−π stacking to study their photodynamic therapy (PDT) efficacy. Photophysiochemical properties of complexes 2, 3, and their conjugates (2-FA-NGQDs, 3-FA-NGQDs) were studied. It was found that complex 3 had higher ϕΔ of 0.56 compared to complex 2 with ϕΔ of 0.24, and respective composites: 3-FA-NGQDs had higher ϕΔ compared to 2-FA-NGQDs. The PDT studies were conducted for nanoparticles (FA-NGQDs), complexes (2, 3), and respective composites (2-FA-NGQDs, and 3-FA-NGQDs) using MCF-7 breast cancer cell. Dark toxicity of all compounds was above 90% which is negligible. At a highest concentration of 40 µg/mL, 3-FA-NGQDs gave the lowest cell viability of 28% compared to all other conjugates and porphyrins alone.
- Full Text:
- Date Issued: 2022
Assessing the electrocatalytic activity of a localized push-pull system in cobalt phthalocyanine/graphene quantum dot hybrids
- Nkhahle, Reitumetse, Nyokong, Tebello
- Authors: Nkhahle, Reitumetse , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229909 , vital:49722 , xlink:href="https://doi.org/10.1016/j.matchemphys.2022.125842"
- Description: In this study, two cobalt phthalocyanines (asymmetric complex 1) and symmetric (complex 2) were synthesized and conjugated to nitrogen-doped graphene quantum dots (NGQDs) through covalent and non-covalent means to create Co phthalocyanine (CoPc)-NGQDs hybrid systems. The CoPcs and conjugates were applied as electrode modifiers on a glassy carbon electrode in the electrochemical sensing of nitrite. Of the CoPcs alone, complex 1 performed better than complex 2 regarding the limits of detection (LoD) recorded (5.74 μM for 1 and 15.1 μM for 2). Regarding the conjugates/nanocomposites, the π-π stacked conjugate derived from complex 2 (2πNGQDs) demonstrated highly favourable electrochemical potential with an LoD value of 0.70 μM. The nanocomposites fashioned from complex 1 were marred by a reduced loading which rendered the conjugates poor electrochemical sensors. These observations however do not disqualify GQDs as complementary nanomaterials to phthalocyanines but rather shed light on seeking alternative routes to increasing the Pc loading in conjugates (more so in π-π stacked conjugates).
- Full Text:
- Date Issued: 2022
- Authors: Nkhahle, Reitumetse , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229909 , vital:49722 , xlink:href="https://doi.org/10.1016/j.matchemphys.2022.125842"
- Description: In this study, two cobalt phthalocyanines (asymmetric complex 1) and symmetric (complex 2) were synthesized and conjugated to nitrogen-doped graphene quantum dots (NGQDs) through covalent and non-covalent means to create Co phthalocyanine (CoPc)-NGQDs hybrid systems. The CoPcs and conjugates were applied as electrode modifiers on a glassy carbon electrode in the electrochemical sensing of nitrite. Of the CoPcs alone, complex 1 performed better than complex 2 regarding the limits of detection (LoD) recorded (5.74 μM for 1 and 15.1 μM for 2). Regarding the conjugates/nanocomposites, the π-π stacked conjugate derived from complex 2 (2πNGQDs) demonstrated highly favourable electrochemical potential with an LoD value of 0.70 μM. The nanocomposites fashioned from complex 1 were marred by a reduced loading which rendered the conjugates poor electrochemical sensors. These observations however do not disqualify GQDs as complementary nanomaterials to phthalocyanines but rather shed light on seeking alternative routes to increasing the Pc loading in conjugates (more so in π-π stacked conjugates).
- Full Text:
- Date Issued: 2022
Lessons from COVID-19 for wildlife ranching in a changing world
- Clements, Hayley S, Child, Matthew F, Lindeque, Lehman, Lunderstedt, Kyra, de Vos, Alta
- Authors: Clements, Hayley S , Child, Matthew F , Lindeque, Lehman , Lunderstedt, Kyra , de Vos, Alta
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/415886 , vital:71297 , xlink:href="https://doi.org/10.1038/s41893-022-00961-1"
- Description: The COVID-19 pandemic provided an opportunity to assess the impacts of a global disturbance on conservation land uses and learn from responses to the crisis to enable more resilient conservation systems. To understand socio-economic responses of diverse wildlife working lands to COVID-19, we surveyed owners and managers of 78 private wildlife ranches (wildlife working lands), 23 agricultural farms (conventional working lands) and six public protected areas (conventional conservation lands) in South Africa. Most protected areas lost more than 75% of their revenues during 2020, while most agricultural farms lost less than 10%. The impact on wildlife ranches was more varied. Ranches with more diverse activities, particularly mixed wildlife–agriculture systems, lost less revenue, shifting their activities from those heavily impacted (international ecotourism, trophy hunting) to those less afected (for example, wildlife meat, livestock). This adaptive capacity suggests that wildlife-based enterprises could represent key ecosystem-based adaptations, providing lessons for integrated global policies that seek to incorporate private land models in the 2030 Biodiversity Framework.
- Full Text:
- Date Issued: 2022
- Authors: Clements, Hayley S , Child, Matthew F , Lindeque, Lehman , Lunderstedt, Kyra , de Vos, Alta
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/415886 , vital:71297 , xlink:href="https://doi.org/10.1038/s41893-022-00961-1"
- Description: The COVID-19 pandemic provided an opportunity to assess the impacts of a global disturbance on conservation land uses and learn from responses to the crisis to enable more resilient conservation systems. To understand socio-economic responses of diverse wildlife working lands to COVID-19, we surveyed owners and managers of 78 private wildlife ranches (wildlife working lands), 23 agricultural farms (conventional working lands) and six public protected areas (conventional conservation lands) in South Africa. Most protected areas lost more than 75% of their revenues during 2020, while most agricultural farms lost less than 10%. The impact on wildlife ranches was more varied. Ranches with more diverse activities, particularly mixed wildlife–agriculture systems, lost less revenue, shifting their activities from those heavily impacted (international ecotourism, trophy hunting) to those less afected (for example, wildlife meat, livestock). This adaptive capacity suggests that wildlife-based enterprises could represent key ecosystem-based adaptations, providing lessons for integrated global policies that seek to incorporate private land models in the 2030 Biodiversity Framework.
- Full Text:
- Date Issued: 2022
Photodegradation of ibuprofen using 5-10-15-20-tetrakis (4-bromophenyl) porphyrin conjugated to graphene quantum dots
- Magaela, Bridged N, Ndlovu, Knowledge S, Tshangana, Charmaine S, Muleia, Adoph A, Mamba, Bhekie B, Nyokong, Tebello, Managa, Muthumuni
- Authors: Magaela, Bridged N , 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, Bridged N , 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
The contribution of wild palms to the livelihoods and diversification of rural households in southern Mozambique
- King, Angelina R, Shackleton, Charlie M
- Authors: King, Angelina R , Shackleton, Charlie M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/399846 , vital:69563 , xlink:href="https://doi.org/10.1016/j.forpol.2022.102793"
- Description: In most low-income countries, rural households combine a range of economic activities to generate income, achieve food and nutritional security and fulfill other livelihood objectives, including: small-scale farming, fishing, hunting, livestock and timber production, and non-timber forest products gathering, as well as off-farm activities such as wage labour and informal trading. This work examines the role of diversification, including palm products income, on rural livelihoods in the Zitundo area, southern Mozambique. Seven livelihood strategies were identified, with every strategy combining cash income from several sources. Most households adopt a wage-based strategy to some degree, although this strategy shows low potential for reducing poverty in the area. Households adopting a palm-based strategy show between 23% and 60% lower poverty incidence than those adopting alternatives strategies. Yet, a palm-based livelihood strategy was adopted by only 11% of households. Traders of palm products earn approximately double the annual income and per capita income than non-traders. Village of residency and some household socio-economic and demographic characteristics correlate with a households' choice of livelihood strategy and palm income dependency. The adherence of many households to a less remunerative wage strategy indicates other factors also influence the choice of livelihood strategies. The study shows that future development plans and policy interventions to mitigate poverty in the area should go beyond the usual agricultural sector and recognize the role of non-timber forest products, especially palm products, for people's livelihoods and poverty alleviation.
- Full Text:
- Date Issued: 2022
- Authors: King, Angelina R , Shackleton, Charlie M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/399846 , vital:69563 , xlink:href="https://doi.org/10.1016/j.forpol.2022.102793"
- Description: In most low-income countries, rural households combine a range of economic activities to generate income, achieve food and nutritional security and fulfill other livelihood objectives, including: small-scale farming, fishing, hunting, livestock and timber production, and non-timber forest products gathering, as well as off-farm activities such as wage labour and informal trading. This work examines the role of diversification, including palm products income, on rural livelihoods in the Zitundo area, southern Mozambique. Seven livelihood strategies were identified, with every strategy combining cash income from several sources. Most households adopt a wage-based strategy to some degree, although this strategy shows low potential for reducing poverty in the area. Households adopting a palm-based strategy show between 23% and 60% lower poverty incidence than those adopting alternatives strategies. Yet, a palm-based livelihood strategy was adopted by only 11% of households. Traders of palm products earn approximately double the annual income and per capita income than non-traders. Village of residency and some household socio-economic and demographic characteristics correlate with a households' choice of livelihood strategy and palm income dependency. The adherence of many households to a less remunerative wage strategy indicates other factors also influence the choice of livelihood strategies. The study shows that future development plans and policy interventions to mitigate poverty in the area should go beyond the usual agricultural sector and recognize the role of non-timber forest products, especially palm products, for people's livelihoods and poverty alleviation.
- Full Text:
- Date Issued: 2022
The in vitro photo-sonodynamic combinatorial therapy activity of cationic and zwitterionic phthalocyanines on MCF-7 and HeLa cancer cell lines
- Nene, Lindokuhle Cindy, Buthelezi, Khanyisile, Prinsloo, Earl, Nyokong, Tebello
- Authors: Nene, Lindokuhle Cindy , Buthelezi, Khanyisile , Prinsloo, Earl , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295891 , vital:57387 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114116"
- Description: The syntheses and characterization studies of zwitterionic 2,9,16,23-tetrakis-(N-propane sultone-morpholino) zinc(II) (4) and 2,9,16,23-tetrakis-(2,5-dimethyl-4-(N-propane sultone-morpholinomethyl))-phenoxy zinc(II) (6) phthalocyanines are reported in this work. The photophysical properties, reactive oxygen species (ROS) generation and in vitro anticancer photodynamic (PDT), sonodynamic (SDT), and photo-sonodynamic combination (PSDT) therapy activities of the Pcs were studied and compared to their cationic counterparts: (2,9,16,23-tetrakis-(N-methyl-morpholino) Zn(II)Pc, 3), (2,9,16,23-tetrakis-(2,5-dimethyl-4-(N-methylmorpholine)-phenoxy) Zn(II)Pc, 5). The cationic Pcs maintained higher anticancer activity for all treatment types and had higher ROS generation compared to the zwitterionic Pcs. Singlet oxygen and hydroxyl radicals were generated during ultrasound and combination irradiations of the Pcs. The zwitterionic Pcs also generated carbon radicals under ultrasound and combination irradiations. The ability of the Pcs to generate ROS is essential for PDT, SDT and PSDT, thus making these Pcs potential anticancer probes for these treatment types. Furthermore, the Pcs demonstrated the ability to bind to bovine serum albumin protein.
- Full Text:
- Date Issued: 2022
- Authors: Nene, Lindokuhle Cindy , Buthelezi, Khanyisile , Prinsloo, Earl , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295891 , vital:57387 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114116"
- Description: The syntheses and characterization studies of zwitterionic 2,9,16,23-tetrakis-(N-propane sultone-morpholino) zinc(II) (4) and 2,9,16,23-tetrakis-(2,5-dimethyl-4-(N-propane sultone-morpholinomethyl))-phenoxy zinc(II) (6) phthalocyanines are reported in this work. The photophysical properties, reactive oxygen species (ROS) generation and in vitro anticancer photodynamic (PDT), sonodynamic (SDT), and photo-sonodynamic combination (PSDT) therapy activities of the Pcs were studied and compared to their cationic counterparts: (2,9,16,23-tetrakis-(N-methyl-morpholino) Zn(II)Pc, 3), (2,9,16,23-tetrakis-(2,5-dimethyl-4-(N-methylmorpholine)-phenoxy) Zn(II)Pc, 5). The cationic Pcs maintained higher anticancer activity for all treatment types and had higher ROS generation compared to the zwitterionic Pcs. Singlet oxygen and hydroxyl radicals were generated during ultrasound and combination irradiations of the Pcs. The zwitterionic Pcs also generated carbon radicals under ultrasound and combination irradiations. The ability of the Pcs to generate ROS is essential for PDT, SDT and PSDT, thus making these Pcs potential anticancer probes for these treatment types. Furthermore, the Pcs demonstrated the ability to bind to bovine serum albumin protein.
- Full Text:
- Date Issued: 2022
A Sn (iv) porphyrin with mitochondria targeting properties for enhanced photodynamic activity against MCF-7 cells
- Babu, Balaji, Mack, John, Nyokong, Tebello
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230897 , vital:49829 , xlink:href="https://doi.org/10.1039/D2NJ00350C"
- Description: Two readily synthesized Sn(IV) porphyrins (SnP, SnPH) have been prepared with and without the cationic triphenylphosphonium moiety (TPP+), which have high singlet oxygen quantum yields (ca. 0.72) and long triplet state lifetimes. The Sn(IV) porphyrin with a TPP+ moiety (SnPH) exhibits favorable photodynamic activity against MCF-7 cells with IC50 values of 2.9 μM. SnPH exhibits higher cellular uptake than SnP in MCF-7 cells. A Rhodamine 123 (Rh123) assay showed that SnPH targets mitochondria and induces apoptosis by generating reactive oxygen species. The results demonstrate that this structural modification strategy merits further in-depth study.
- Full Text:
- Date Issued: 2022
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230897 , vital:49829 , xlink:href="https://doi.org/10.1039/D2NJ00350C"
- Description: Two readily synthesized Sn(IV) porphyrins (SnP, SnPH) have been prepared with and without the cationic triphenylphosphonium moiety (TPP+), which have high singlet oxygen quantum yields (ca. 0.72) and long triplet state lifetimes. The Sn(IV) porphyrin with a TPP+ moiety (SnPH) exhibits favorable photodynamic activity against MCF-7 cells with IC50 values of 2.9 μM. SnPH exhibits higher cellular uptake than SnP in MCF-7 cells. A Rhodamine 123 (Rh123) assay showed that SnPH targets mitochondria and induces apoptosis by generating reactive oxygen species. The results demonstrate that this structural modification strategy merits further in-depth study.
- Full Text:
- Date Issued: 2022
Integrated photocatalyst adsorbents based on porphyrin anchored to activated carbon granules for water treatment
- Oyim, James, Amuhaya, Edith, Matshitse, Refilwe, Mack, John, Nyokong, Tebello
- Authors: Oyim, James , Amuhaya, Edith , Matshitse, Refilwe , Mack, John , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300101 , vital:57893 , xlink:href="https://doi.org/10.1016/j.cartre.2022.100191"
- Description: Integration of adsorption and photocatalysis processes can lead to several benefits in water treatment. Integrating well-known adsorbents with photocatalysts ensures that all the interesting components are preserved and helps to overcome the serious downsides of each material and technique when operated independently. In this work, we introduce a new concept of combining both absorption and photodegradation mechanisms using organic photocatalytic adsorbents for water purification. This was achieved by formulating photosensitizing hybrids based on a newly synthesized chloroindium (III) 5,10,15,20-tetrakis(4-acetamidophenyl) porphyrin (InTAAP) compound, anchored on oxygen functionalized coconut shell-based activated carbon granules supports. The fashioned integrated photocatalyst adsorbent hybrid (InTAAP(ACO)) was then studied for their adsorption and photodegradation efficiency using methylene blue dye, where InTAAP(ACO) showed excellent photocatalytic activity compared to ACO and unfunctionalized activated carbon granules (AC), with appreciably high and adsorption properties as AC and ACO.
- Full Text:
- Date Issued: 2022
- Authors: Oyim, James , Amuhaya, Edith , Matshitse, Refilwe , Mack, John , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300101 , vital:57893 , xlink:href="https://doi.org/10.1016/j.cartre.2022.100191"
- Description: Integration of adsorption and photocatalysis processes can lead to several benefits in water treatment. Integrating well-known adsorbents with photocatalysts ensures that all the interesting components are preserved and helps to overcome the serious downsides of each material and technique when operated independently. In this work, we introduce a new concept of combining both absorption and photodegradation mechanisms using organic photocatalytic adsorbents for water purification. This was achieved by formulating photosensitizing hybrids based on a newly synthesized chloroindium (III) 5,10,15,20-tetrakis(4-acetamidophenyl) porphyrin (InTAAP) compound, anchored on oxygen functionalized coconut shell-based activated carbon granules supports. The fashioned integrated photocatalyst adsorbent hybrid (InTAAP(ACO)) was then studied for their adsorption and photodegradation efficiency using methylene blue dye, where InTAAP(ACO) showed excellent photocatalytic activity compared to ACO and unfunctionalized activated carbon granules (AC), with appreciably high and adsorption properties as AC and ACO.
- Full Text:
- Date Issued: 2022