Synthesis, in vitro cytotoxicity and trypanocidal evaluation of novel 1, 3, 6-substituted non-fluoroquinolones
- Beteck, Richard M, Isaacs, Michelle, Khanye, Setshaba D, Hoppe, Heinrich C
- Authors: Beteck, Richard M , Isaacs, Michelle , Khanye, Setshaba D , Hoppe, Heinrich C
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123140 , vital:35409 , https://doi.org/10.17159/0379-4350/2018/v71a25
- Description: Sleeping sickness (trypanosomiasis) is a neglected tropical disease that affects mostly the poorest communities in sub-Saharan Africa. Toxic side effects associated with the use of current anti-trypanosomal drugs, which in some cases kill faster than the disease itself, necessitate the search for new drugs with better safety margins. To this effect, a small library bearing different substituents at position -1, -3, and -6 of the quinolone nucleus were synthesized and evaluated in vitro against HeLa cell lines and Trypanosoma brucei brucei for cytotoxicity and trypanocidal potentials, respectively. While most of these compounds showed no cytotoxic effect, they exhibited moderate to weak anti-trypanosomal activities. The SAR studies of this series provide new information worth considering in future exploration of the quinolone scaffold in search ofmore potent and safe trypanocidal agents.
- Full Text:
- Date Issued: 2018
- Authors: Beteck, Richard M , Isaacs, Michelle , Khanye, Setshaba D , Hoppe, Heinrich C
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123140 , vital:35409 , https://doi.org/10.17159/0379-4350/2018/v71a25
- Description: Sleeping sickness (trypanosomiasis) is a neglected tropical disease that affects mostly the poorest communities in sub-Saharan Africa. Toxic side effects associated with the use of current anti-trypanosomal drugs, which in some cases kill faster than the disease itself, necessitate the search for new drugs with better safety margins. To this effect, a small library bearing different substituents at position -1, -3, and -6 of the quinolone nucleus were synthesized and evaluated in vitro against HeLa cell lines and Trypanosoma brucei brucei for cytotoxicity and trypanocidal potentials, respectively. While most of these compounds showed no cytotoxic effect, they exhibited moderate to weak anti-trypanosomal activities. The SAR studies of this series provide new information worth considering in future exploration of the quinolone scaffold in search ofmore potent and safe trypanocidal agents.
- Full Text:
- Date Issued: 2018
Synthesis, photophysicochemical and photodynamic antimicrobial chemotherapy studies of indium pyridyl phthalocyanines: Charge versus bridging atom
- Sindelo, Azole, Nyokong, Tebello
- Authors: Sindelo, Azole , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187650 , vital:44683 , xlink:href="https://doi.org/10.1016/j.ica.2018.02.020"
- Description: 2(3), 9(10), 16(17), 23(24)-Octapyridylsulfanyl phthalocyaninato chloroindium(III) (complex 1a) and its quaternized derivative 2(3), 9(10), 16(17), 23(24)-octamethylpyridylsulfanyl phthalocyaninato chloroindium (III) (complex 1b) were synthesised. The triplet quantum yields were 0.53 and 0.48 while the singlet oxygen quantum yields were 0.46 and 0.33 in DMF for 1a and 1b, respectively. The photodynamic antimicrobial chemotherapy (PACT) activity of 1b (containing 8 positive charges) was compared to those of 9(10),16(17),23(24)-tri-N-methyl-4-pyridylsulfanyl-2(3)-(4-aminophenoxy) phthalocyaninato chloro indium(III) triiodide (2) (containing 3 positive charges) and 2-[4-(N-Methylpyridyloxy) phthalocyaninato] chloroindium (III) iodide (3) (containing 4 positive charges). Complex 1b gave log reductions of 4.21, 8.30 and 3.21 for Gram(−) E. coli, Gram(+) S. aureus and C. albicans, respectively. When comparing 1b, 2 and 3, the largest log reductions for E. coli were obtained for complex 3 containing four positive charges hence showing it is not always the charge that determines the PACT activity, but the bridging atom in the phthalocyanine plays a role.
- Full Text:
- Date Issued: 2018
- Authors: Sindelo, Azole , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187650 , vital:44683 , xlink:href="https://doi.org/10.1016/j.ica.2018.02.020"
- Description: 2(3), 9(10), 16(17), 23(24)-Octapyridylsulfanyl phthalocyaninato chloroindium(III) (complex 1a) and its quaternized derivative 2(3), 9(10), 16(17), 23(24)-octamethylpyridylsulfanyl phthalocyaninato chloroindium (III) (complex 1b) were synthesised. The triplet quantum yields were 0.53 and 0.48 while the singlet oxygen quantum yields were 0.46 and 0.33 in DMF for 1a and 1b, respectively. The photodynamic antimicrobial chemotherapy (PACT) activity of 1b (containing 8 positive charges) was compared to those of 9(10),16(17),23(24)-tri-N-methyl-4-pyridylsulfanyl-2(3)-(4-aminophenoxy) phthalocyaninato chloro indium(III) triiodide (2) (containing 3 positive charges) and 2-[4-(N-Methylpyridyloxy) phthalocyaninato] chloroindium (III) iodide (3) (containing 4 positive charges). Complex 1b gave log reductions of 4.21, 8.30 and 3.21 for Gram(−) E. coli, Gram(+) S. aureus and C. albicans, respectively. When comparing 1b, 2 and 3, the largest log reductions for E. coli were obtained for complex 3 containing four positive charges hence showing it is not always the charge that determines the PACT activity, but the bridging atom in the phthalocyanine plays a role.
- Full Text:
- Date Issued: 2018
Temporal dynamics and motivations for urban community food gardens in medium-sized towns of the Eastern Cape, South Africa
- Roberts, Sky, Shackleton, Charlie M
- Authors: Roberts, Sky , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179768 , vital:43178 , xlink:href="https://doi.org/10.3390/land7040146"
- Description: Urban agriculture is said to be increasing with global urbanization. However, there is little examination of the temporal or spatial dynamics of urban agriculture. We investigated the benefits and challenges experienced by community gardeners in four towns in South Africa, along with GIS analysis of the number, area, and location of urban food community gardens over the last three decades. Common reasons for practicing community gardening were cash poverty (37%) and the need to grow food (34%). The most common benefits reported by respondents were a healthy lifestyle (58%) and consumption of the food produced (54%). Theft of garden infrastructure or produce was a noteworthy challenge to continued motivation and engagement in urban community gardening. There were declines in the number and area of urban community gardens, and more central location over the last three decades. Only 16% of the gardens present in the 1980s were still operating in the 2000s. Clearly community gardening is temporally and spatially dynamic, which requires context-sensitive policy initiatives.
- Full Text:
- Date Issued: 2018
- Authors: Roberts, Sky , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179768 , vital:43178 , xlink:href="https://doi.org/10.3390/land7040146"
- Description: Urban agriculture is said to be increasing with global urbanization. However, there is little examination of the temporal or spatial dynamics of urban agriculture. We investigated the benefits and challenges experienced by community gardeners in four towns in South Africa, along with GIS analysis of the number, area, and location of urban food community gardens over the last three decades. Common reasons for practicing community gardening were cash poverty (37%) and the need to grow food (34%). The most common benefits reported by respondents were a healthy lifestyle (58%) and consumption of the food produced (54%). Theft of garden infrastructure or produce was a noteworthy challenge to continued motivation and engagement in urban community gardening. There were declines in the number and area of urban community gardens, and more central location over the last three decades. Only 16% of the gardens present in the 1980s were still operating in the 2000s. Clearly community gardening is temporally and spatially dynamic, which requires context-sensitive policy initiatives.
- Full Text:
- Date Issued: 2018
The contributions of biological control to reduced plant size and biomass of water hyacinth populations
- Jones, Roy W, Hill, Jaclyn M, Coetzee, Julie A, Hill, Martin P
- Authors: Jones, Roy W , Hill, Jaclyn M , Coetzee, Julie A , Hill, Martin P
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68803 , vital:29326 , https://0-doi.org.wam.seals.ac.za/10.1007/s10750-017-3413-y
- Description: Water hyacinth is invasive in many countries, where it reduces aquatic biodiversity and limits water resource utilisation. Biological control of water hyacinth has been successful in South Africa, but has suffered from a lack of empirical data to prove causation. Insect exclusion trials were conducted to quantify the contribution of Neochetina eichhorniae and N. bruchi to the integrated control of water hyacinth on the Nseleni River, South Africa. Insecticide was not expected to induce phytotoxicity, but would prevent weevil damage in water hyacinth plants; and weevil herbivory was predicted to reduce plant petiole length, and above/below surface biomass. Results showed that insecticide had no phytotoxic effects and excluded weevils for 3 weeks, providing a baseline for field applications. Biological control on the Nseleni River directly affected water hyacinth biomass and petiole length, but did not affect plant cover. Plants subject to weevil herbivory demonstrated reductions in above and below surface biomass and had shorter petioles compared to insect-free plants. Dead biomass was also higher in biological control treatments. Biological control strongly affects plant size, biomass and vigour; however, further integrated control is required to facilitate reduction in mat cover, which is the goalpost for successful control of floating aquatic plants.
- Full Text: false
- Date Issued: 2018
- Authors: Jones, Roy W , Hill, Jaclyn M , Coetzee, Julie A , Hill, Martin P
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68803 , vital:29326 , https://0-doi.org.wam.seals.ac.za/10.1007/s10750-017-3413-y
- Description: Water hyacinth is invasive in many countries, where it reduces aquatic biodiversity and limits water resource utilisation. Biological control of water hyacinth has been successful in South Africa, but has suffered from a lack of empirical data to prove causation. Insect exclusion trials were conducted to quantify the contribution of Neochetina eichhorniae and N. bruchi to the integrated control of water hyacinth on the Nseleni River, South Africa. Insecticide was not expected to induce phytotoxicity, but would prevent weevil damage in water hyacinth plants; and weevil herbivory was predicted to reduce plant petiole length, and above/below surface biomass. Results showed that insecticide had no phytotoxic effects and excluded weevils for 3 weeks, providing a baseline for field applications. Biological control on the Nseleni River directly affected water hyacinth biomass and petiole length, but did not affect plant cover. Plants subject to weevil herbivory demonstrated reductions in above and below surface biomass and had shorter petioles compared to insect-free plants. Dead biomass was also higher in biological control treatments. Biological control strongly affects plant size, biomass and vigour; however, further integrated control is required to facilitate reduction in mat cover, which is the goalpost for successful control of floating aquatic plants.
- Full Text: false
- Date Issued: 2018
The determination of CHARMM force field parameters for the Mg2+ containing HIV-1 integrase:
- Musyoka, Thommas, Tastan Bishop, Özlem, Lobb, Kevin A, Moses, Vuyani
- Authors: Musyoka, Thommas , Tastan Bishop, Özlem , Lobb, Kevin A , Moses, Vuyani
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148139 , vital:38713 , DOI: 10.1016/j.cplett.2018.09.019
- Description: The HIV integrase enzyme is a validated drug target. However, its potential has remained largely unexploited until recently due to lack of structural and mechanistic information. Its catalytic core domain (CCD) is crucial for the viral-human DNA integration making integrase an ideal target for inhibitor design. However, in order to do so, force field parameters for the integrase magnesium ion need to be established. Quantum mechanical calculations were used to derive force field parameters which were validated through molecular dynamics studies. Our results show that the parameters determined accurately maintain the integrity of the metal pocket of the integrase CCD.
- Full Text:
- Date Issued: 2018
- Authors: Musyoka, Thommas , Tastan Bishop, Özlem , Lobb, Kevin A , Moses, Vuyani
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148139 , vital:38713 , DOI: 10.1016/j.cplett.2018.09.019
- Description: The HIV integrase enzyme is a validated drug target. However, its potential has remained largely unexploited until recently due to lack of structural and mechanistic information. Its catalytic core domain (CCD) is crucial for the viral-human DNA integration making integrase an ideal target for inhibitor design. However, in order to do so, force field parameters for the integrase magnesium ion need to be established. Quantum mechanical calculations were used to derive force field parameters which were validated through molecular dynamics studies. Our results show that the parameters determined accurately maintain the integrity of the metal pocket of the integrase CCD.
- Full Text:
- Date Issued: 2018
The distribution and abundance of the stem-galling fly, Cecidochares connexa (Macquart)(Diptera: Tephritidae), a biological control agent of Chromolaena odorata (L.)(Asteraceae), in Ghana
- Aigbedion-Atalor, Pascal O, Wilson, DD, Eziah, Vincent Y, Day, M, Paterson, Iain D
- Authors: Aigbedion-Atalor, Pascal O , Wilson, DD , Eziah, Vincent Y , Day, M , Paterson, Iain D
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/407074 , vital:70334 , xlink:href="https://hdl.handle.net/10520/EJC-113112d1da"
- Description: Chromolaena odorata (L.) R.M. King and H. Robinson (Asteraceae: Eupatorieae) is one of the worst invasive weeds in West Africa, and a serious biotic threat to food security. The stem-galling fly, Cecidochares connexa (Macquart) (Diptera: Tephritidae), a biological control agent for C. odorata, was released in the Ivory Coast in 2003 and first detected in Ghana in 2014. The spatiotemporal distribution and abundance of C. connexa in Ghana was determined by country-wide surveys from 2015 to 2016. Galls were found in varying densities across Ghana but gall densities were consistently low east of Lake Volta. A limited survey conducted in the extreme west of Togo in 2016, found the gall fly also in low numbers. There was a significant correlation between C. connexa gall densities and the distance from the release sites in the Ivory Coast. The distribution and abundance of the gall fly in Ghana could be explained by its spread from the original release sites over time and/or the much drier conditions east of Lake Volta. Cecidochares connexa has dispersed a distance of about 1000 km over a 10-year period and, while there is some evidence that the gall fly is still dispersing towards the east, its range and population size could be limited by the dry climatic conditions in the east of Ghana and in Togo. Actively redistributing the agent over this dry corridor to the more humid and higher rainfall areas of Nigeria, may result in the spread of this agent through the rest of West and Central Africa, thereby aiding the control of C. odorata in the region.
- Full Text:
- Date Issued: 2018
- Authors: Aigbedion-Atalor, Pascal O , Wilson, DD , Eziah, Vincent Y , Day, M , Paterson, Iain D
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/407074 , vital:70334 , xlink:href="https://hdl.handle.net/10520/EJC-113112d1da"
- Description: Chromolaena odorata (L.) R.M. King and H. Robinson (Asteraceae: Eupatorieae) is one of the worst invasive weeds in West Africa, and a serious biotic threat to food security. The stem-galling fly, Cecidochares connexa (Macquart) (Diptera: Tephritidae), a biological control agent for C. odorata, was released in the Ivory Coast in 2003 and first detected in Ghana in 2014. The spatiotemporal distribution and abundance of C. connexa in Ghana was determined by country-wide surveys from 2015 to 2016. Galls were found in varying densities across Ghana but gall densities were consistently low east of Lake Volta. A limited survey conducted in the extreme west of Togo in 2016, found the gall fly also in low numbers. There was a significant correlation between C. connexa gall densities and the distance from the release sites in the Ivory Coast. The distribution and abundance of the gall fly in Ghana could be explained by its spread from the original release sites over time and/or the much drier conditions east of Lake Volta. Cecidochares connexa has dispersed a distance of about 1000 km over a 10-year period and, while there is some evidence that the gall fly is still dispersing towards the east, its range and population size could be limited by the dry climatic conditions in the east of Ghana and in Togo. Actively redistributing the agent over this dry corridor to the more humid and higher rainfall areas of Nigeria, may result in the spread of this agent through the rest of West and Central Africa, thereby aiding the control of C. odorata in the region.
- Full Text:
- Date Issued: 2018
The effect of annealing and beta irradiation on thermoluminescence spectra of α-Al2O3: C, Mg
- Kalita, Jitumani M, Chithambo, Makaiko L
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/112875 , vital:33669 , https://doi.org/10.1016/j.jlumin.2017.12.036
- Description: The effect of annealing on thermoluminescence spectra of beta irradiated α-Al2O3:C,Mg has been studied. Measurements were made on an un-annealed sample and samples annealed at 600, 700 and 900 °C. A glow curve measured at 1 °C/s from samples irradiated to 1 Gy shows a high intensity peak at 163 °C and six secondary peaks of weaker intensity at 43, 73, 195, 280, 329 and 370 °C. When the samples are annealed at 700 or 900 °C, an additional secondary peak appears at 100 °C. The thermoluminescence spectrum of an un-annealed sample measured at 1 °C/s between 300 and 700 nm shows the main emission band at ~ 410 nm and subsidiary emission bands at ~ 325 and 485 nm. The emission from samples annealed at 700 and 900 °C show similar bands except for a decrease in intensity of the emission at 485 nm. The emission bands at 325, 410 and 485 nm are attributed to F+, F and F22+(2Mg) -centres respectively. The decrease of the emission band at 485 nm is deduced to be due to the destruction of the F22+(2Mg) centre at 700 °C. The emission bands are unaffected by irradiation dose between 10 and 320 Gy. However, when the sample is annealed at or beyond 700 °C, any effects on the F+ and F centres emission can be easier distinguished particularly for doses greater than 10 Gy.
- Full Text: false
- Date Issued: 2018
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/112875 , vital:33669 , https://doi.org/10.1016/j.jlumin.2017.12.036
- Description: The effect of annealing on thermoluminescence spectra of beta irradiated α-Al2O3:C,Mg has been studied. Measurements were made on an un-annealed sample and samples annealed at 600, 700 and 900 °C. A glow curve measured at 1 °C/s from samples irradiated to 1 Gy shows a high intensity peak at 163 °C and six secondary peaks of weaker intensity at 43, 73, 195, 280, 329 and 370 °C. When the samples are annealed at 700 or 900 °C, an additional secondary peak appears at 100 °C. The thermoluminescence spectrum of an un-annealed sample measured at 1 °C/s between 300 and 700 nm shows the main emission band at ~ 410 nm and subsidiary emission bands at ~ 325 and 485 nm. The emission from samples annealed at 700 and 900 °C show similar bands except for a decrease in intensity of the emission at 485 nm. The emission bands at 325, 410 and 485 nm are attributed to F+, F and F22+(2Mg) -centres respectively. The decrease of the emission band at 485 nm is deduced to be due to the destruction of the F22+(2Mg) centre at 700 °C. The emission bands are unaffected by irradiation dose between 10 and 320 Gy. However, when the sample is annealed at or beyond 700 °C, any effects on the F+ and F centres emission can be easier distinguished particularly for doses greater than 10 Gy.
- Full Text: false
- Date Issued: 2018
The effect of pre-dose on thermally and optically stimulated luminescence from α-Al2O3C, Mg and α-Al2O3: C
- Kalita, Jitumani M, Chithambo, Makaiko L
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/111011 , vital:33363 , https://doi.org/10.1016/j.apradiso.2018.06.012
- Description: We report the effect of pre-dose on the thermoluminescence (TL) and optically stimulated luminescence (OSL) dose response of α-Al2O3:C,Mg and α-Al2O3:C. Before any luminescence measurement, the samples were irradiated with different doses, namely 100, 500 and 1000 Gy to populate the deep electron traps. This is the pre-dose. The results from TL and OSL studies are compared with results from samples used without any pre-measurement dose. The TL glow curves and OSL decay curves of α-Al2O3:C,Mg recorded after pre-doses of 100, 500 and 1000 Gy are identical to those from a sample used without any pre-dose. Further, the TL and OSL dose response of all α-Al2O3:C,Mg samples are similar regardless of pre-dose. In comparison, the TL glow curves and OSL decay curves of α-Al2O3:C are influenced by pre-dose. We conclude that the differences in the TL and OSL dose response of various pre-dosed samples of α-Al2O3:C are due to the concentration of charge in the deep traps. On the other hand, owing to the lower concentration of such deep traps in α-Al2O3:C,Mg, the TL or OSL dose responses are not affected by pre-dose in this material.
- Full Text: false
- Date Issued: 2018
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/111011 , vital:33363 , https://doi.org/10.1016/j.apradiso.2018.06.012
- Description: We report the effect of pre-dose on the thermoluminescence (TL) and optically stimulated luminescence (OSL) dose response of α-Al2O3:C,Mg and α-Al2O3:C. Before any luminescence measurement, the samples were irradiated with different doses, namely 100, 500 and 1000 Gy to populate the deep electron traps. This is the pre-dose. The results from TL and OSL studies are compared with results from samples used without any pre-measurement dose. The TL glow curves and OSL decay curves of α-Al2O3:C,Mg recorded after pre-doses of 100, 500 and 1000 Gy are identical to those from a sample used without any pre-dose. Further, the TL and OSL dose response of all α-Al2O3:C,Mg samples are similar regardless of pre-dose. In comparison, the TL glow curves and OSL decay curves of α-Al2O3:C are influenced by pre-dose. We conclude that the differences in the TL and OSL dose response of various pre-dosed samples of α-Al2O3:C are due to the concentration of charge in the deep traps. On the other hand, owing to the lower concentration of such deep traps in α-Al2O3:C,Mg, the TL or OSL dose responses are not affected by pre-dose in this material.
- Full Text: false
- Date Issued: 2018
The effect of the cobalt and manganese central metal ions on the nonlinear optical properties of tetra (4-propargyloxyphenoxy) phthalocyanines
- Mwanza, Daniel, Louzada, Marcel, Britton, Jonathan, Sekhosana, Kutloano E, Khene, Samson M, Nyokong, Tebello, Mashazi, Philani N
- Authors: Mwanza, Daniel , Louzada, Marcel , Britton, Jonathan , Sekhosana, Kutloano E , Khene, Samson M , Nyokong, Tebello , Mashazi, Philani N
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233357 , vital:50083 , xlink:href="https://doi.org/10.1039/C8NJ00748A"
- Description: The metal-free (H2TPrOPhOPc), cobalt (CoTPrOPhOPc) and manganese (Mn(OAc)TPrOPhOPc) tetra propargyloxyphenoxy phthalocyanines were evaluated for their potential as optical limiting materials. The effect of the substituents and the central metal ions on the nonlinear optical properties was evaluated. The metal-free phthalocyanine exhibited better nonlinear optical properties when compared to the cobalt and manganese complexes owing to the metal ions quenching the excited state due to their half-filled d-orbitals. The nonlinear absorption coefficient (βeff, ×10−5 m MW−1) followed the trend of H2TPrOPhOPc > CoTPrOPhOPc > Mn(OAc)TPrOPhOPc. The values βeff (×10−5 m MW−1) using 532 nm Nd:YAG (560 nm monochromatic Ekspla) laser sources were 23.5 > 14.3 > 9.20 (14.4). The second-order nonlinear coefficient obtained using density functional theory calculations, the theoretical hyper-Rayleigh scattering (βHRS, ×10−28 esu), showed the decreasing trend for H2TPrOPhOPc (2.28) > CoTPrOPhOPc (2.10) > Mn(OAc)TPrOPhOPc (1.86). The 4-(propargyloxy)phenoxy substituents enhanced the optical limiting properties of the synthesized phthalocyanines.
- Full Text:
- Date Issued: 2018
- Authors: Mwanza, Daniel , Louzada, Marcel , Britton, Jonathan , Sekhosana, Kutloano E , Khene, Samson M , Nyokong, Tebello , Mashazi, Philani N
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233357 , vital:50083 , xlink:href="https://doi.org/10.1039/C8NJ00748A"
- Description: The metal-free (H2TPrOPhOPc), cobalt (CoTPrOPhOPc) and manganese (Mn(OAc)TPrOPhOPc) tetra propargyloxyphenoxy phthalocyanines were evaluated for their potential as optical limiting materials. The effect of the substituents and the central metal ions on the nonlinear optical properties was evaluated. The metal-free phthalocyanine exhibited better nonlinear optical properties when compared to the cobalt and manganese complexes owing to the metal ions quenching the excited state due to their half-filled d-orbitals. The nonlinear absorption coefficient (βeff, ×10−5 m MW−1) followed the trend of H2TPrOPhOPc > CoTPrOPhOPc > Mn(OAc)TPrOPhOPc. The values βeff (×10−5 m MW−1) using 532 nm Nd:YAG (560 nm monochromatic Ekspla) laser sources were 23.5 > 14.3 > 9.20 (14.4). The second-order nonlinear coefficient obtained using density functional theory calculations, the theoretical hyper-Rayleigh scattering (βHRS, ×10−28 esu), showed the decreasing trend for H2TPrOPhOPc (2.28) > CoTPrOPhOPc (2.10) > Mn(OAc)TPrOPhOPc (1.86). The 4-(propargyloxy)phenoxy substituents enhanced the optical limiting properties of the synthesized phthalocyanines.
- Full Text:
- Date Issued: 2018
The energy transition patterns of low-income households in South Africa: an evaluation of energy programme and policy
- Israel-Akinbo, Sylvia O, Snowball, Jeanette D, Fraser, Gavin C G
- Authors: Israel-Akinbo, Sylvia O , Snowball, Jeanette D , Fraser, Gavin C G
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69397 , vital:29518 , https://doi.org/10.17159/2413-3051/2018/v29i3a3310
- Description: The transition to modern energy carriers like electricity is an important way to achieve to eradicate energy poverty. This study investigated energy transition patterns and trends in low-income South African households. The marginal effects of the different determinants on the probability of choosing a specific energy carrier were computed and the influence of some endogenous characteristics in transitioning to modern energy carriers was explored. It was found that energy ladder behaviour exists for cooking while energy stacking was most likely for space heating and the pattern for lighting tended towards energy stacking. Dwelling type, household size and geographical location were among the key determinants of the energy transition pattern. Policies to reduce energy poverty need a multi-pronged approach and not only a focus on electricity access.
- Full Text:
- Date Issued: 2018
- Authors: Israel-Akinbo, Sylvia O , Snowball, Jeanette D , Fraser, Gavin C G
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69397 , vital:29518 , https://doi.org/10.17159/2413-3051/2018/v29i3a3310
- Description: The transition to modern energy carriers like electricity is an important way to achieve to eradicate energy poverty. This study investigated energy transition patterns and trends in low-income South African households. The marginal effects of the different determinants on the probability of choosing a specific energy carrier were computed and the influence of some endogenous characteristics in transitioning to modern energy carriers was explored. It was found that energy ladder behaviour exists for cooking while energy stacking was most likely for space heating and the pattern for lighting tended towards energy stacking. Dwelling type, household size and geographical location were among the key determinants of the energy transition pattern. Policies to reduce energy poverty need a multi-pronged approach and not only a focus on electricity access.
- Full Text:
- Date Issued: 2018
The generation and characterisation of neutralising antibodies against the Theiler’s murine encephalomyelitis virus (TMEV) GDVII capsid reveals the potential binding site of the host cell co-receptor, heparan sulfate:
- Upfold, Nicole, Ross, Caroline J, Tastan Bishop, Özlem, Luke, Garry A, Knox, Caroline M
- Authors: Upfold, Nicole , Ross, Caroline J , Tastan Bishop, Özlem , Luke, Garry A , Knox, Caroline M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148181 , vital:38717 , DOI: 10.1016/j.virusres.2017.11.017
- Description: The early stages of picornavirus capsid assembly and the host factors involved are poorly understood. Since the localisation of viral proteins in infected cells can provide information on their function, antibodies against purified Theiler's murine encephalomyelitis virus (TMEV) GDVII capsids were generated by immunisation of rabbits. The resultant anti-TMEV capsid antibodies recognised a C-terminal region of VP1 but not VP2 or VP3 by Western analysis. Examination of the sites of TMEV capsid assembly by indirect immunofluorescence and confocal microscopy showed that at 5 h post infection, capsid signal was diffusely cytoplasmic with strong perinuclear staining and moved into large punctate structures from 6 to 8 h post infection.
- Full Text:
- Date Issued: 2018
- Authors: Upfold, Nicole , Ross, Caroline J , Tastan Bishop, Özlem , Luke, Garry A , Knox, Caroline M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148181 , vital:38717 , DOI: 10.1016/j.virusres.2017.11.017
- Description: The early stages of picornavirus capsid assembly and the host factors involved are poorly understood. Since the localisation of viral proteins in infected cells can provide information on their function, antibodies against purified Theiler's murine encephalomyelitis virus (TMEV) GDVII capsids were generated by immunisation of rabbits. The resultant anti-TMEV capsid antibodies recognised a C-terminal region of VP1 but not VP2 or VP3 by Western analysis. Examination of the sites of TMEV capsid assembly by indirect immunofluorescence and confocal microscopy showed that at 5 h post infection, capsid signal was diffusely cytoplasmic with strong perinuclear staining and moved into large punctate structures from 6 to 8 h post infection.
- Full Text:
- Date Issued: 2018
The green economy learning assessment South Africa: Lessons for higher education, skills and work-based learning
- Rosenberg, Eureta, Lotz-Sisitka, Heila, Ramsarup, Presha
- Authors: Rosenberg, Eureta , Lotz-Sisitka, Heila , Ramsarup, Presha
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182765 , vital:43872 , xlink:href="https://doi.org/10.1108/HESWBL-03-2018-0041"
- Description: The purpose of this paper is to share and analyse the methodology and findings of the 2016 Green Economy Learning Assessment South Africa, including learning needs identified with reference to the competency framings of Scharmer (2009) and Wiek et al. (2011); and implications for university and work-based sustainability education, broadly conceptualised in a just transitions framework. The assessment was conducted using desktop policy reviews and an audit of sustainability education providers, online questionnaires to sector experts, focus groups and interviews with practitioners driving green economy initiatives. Policy monitoring and evaluation, and education for sustainable development, emerged as key change levers across nine priority areas including agriculture, energy, natural resources, water, transport and infrastructure. The competencies required to drive sustainability in these areas were clustered as technical, relational and transformational competencies for: making the case; integrated sustainable development planning; strategic adaptive management and expansive learning; working across organisational units; working across knowledge fields; capacity and organisational development; and principle-based leadership. Practitioners develop such competencies through formal higher education and short courses plus course-activated networks and “on the job” learning. The paper adds to the literature on sustainability competencies and raises questions regarding forms of hybrid learning suitable for developing technical, relational and transformative competencies. A national learning needs assessment methodology and tools for customised organisational learning needs assessments are shared. The assessment methodology is novel in this context and the workplace-based tools, original.
- Full Text:
- Date Issued: 2018
- Authors: Rosenberg, Eureta , Lotz-Sisitka, Heila , Ramsarup, Presha
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182765 , vital:43872 , xlink:href="https://doi.org/10.1108/HESWBL-03-2018-0041"
- Description: The purpose of this paper is to share and analyse the methodology and findings of the 2016 Green Economy Learning Assessment South Africa, including learning needs identified with reference to the competency framings of Scharmer (2009) and Wiek et al. (2011); and implications for university and work-based sustainability education, broadly conceptualised in a just transitions framework. The assessment was conducted using desktop policy reviews and an audit of sustainability education providers, online questionnaires to sector experts, focus groups and interviews with practitioners driving green economy initiatives. Policy monitoring and evaluation, and education for sustainable development, emerged as key change levers across nine priority areas including agriculture, energy, natural resources, water, transport and infrastructure. The competencies required to drive sustainability in these areas were clustered as technical, relational and transformational competencies for: making the case; integrated sustainable development planning; strategic adaptive management and expansive learning; working across organisational units; working across knowledge fields; capacity and organisational development; and principle-based leadership. Practitioners develop such competencies through formal higher education and short courses plus course-activated networks and “on the job” learning. The paper adds to the literature on sustainability competencies and raises questions regarding forms of hybrid learning suitable for developing technical, relational and transformative competencies. A national learning needs assessment methodology and tools for customised organisational learning needs assessments are shared. The assessment methodology is novel in this context and the workplace-based tools, original.
- Full Text:
- Date Issued: 2018
The investigation of in vitro dark cytotoxicity and photodynamic therapy effect of a 2, 6-dibromo-3, 5-distyryl BODIPY dye encapsulated in Pluronic® F-127 micelles
- Molupe, Nthabeleng, Babu, Balaji, Oluwole, David O, Prinsloo, Earl, Mack, John, Nyokong, Tebello
- Authors: Molupe, Nthabeleng , Babu, Balaji , Oluwole, David O , Prinsloo, Earl , Mack, John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187862 , vital:44704 , xlink:href="https://doi.org/10.1080/00958972.2018.1522536"
- Description: A 2,6-dibrominated 3,5-distyryl boron-dipyrromethene (BODIPY) dye with a moderately high singlet oxygen quantum yield was encapsulated in Pluronic® F-127 micelles, and its dark cytotoxicity and photodynamic activity were investigated on the human breast adenocarcinoma MCF-7 cell line. The BODIPY dye exhibited very low dark toxicity and a significant PDT effect when added in drug formulations consisting of 5.0% (v/v) DMSO in supplemented Dulbecco’s modified Eagle’s medium (DMEM) and as Pluronic® F-127 micelle encapsulation complexes in supplemented DMEM alone. An IC50 value of 4 ± 2 μM was obtained when the BODIPY dye was encapsulated in Pluronic® F-127 micelles during in vitro photodynamic activity studies in MCF-7 cancer cells with a 660 nm light emitting diode.
- Full Text:
- Date Issued: 2018
- Authors: Molupe, Nthabeleng , Babu, Balaji , Oluwole, David O , Prinsloo, Earl , Mack, John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187862 , vital:44704 , xlink:href="https://doi.org/10.1080/00958972.2018.1522536"
- Description: A 2,6-dibrominated 3,5-distyryl boron-dipyrromethene (BODIPY) dye with a moderately high singlet oxygen quantum yield was encapsulated in Pluronic® F-127 micelles, and its dark cytotoxicity and photodynamic activity were investigated on the human breast adenocarcinoma MCF-7 cell line. The BODIPY dye exhibited very low dark toxicity and a significant PDT effect when added in drug formulations consisting of 5.0% (v/v) DMSO in supplemented Dulbecco’s modified Eagle’s medium (DMEM) and as Pluronic® F-127 micelle encapsulation complexes in supplemented DMEM alone. An IC50 value of 4 ± 2 μM was obtained when the BODIPY dye was encapsulated in Pluronic® F-127 micelles during in vitro photodynamic activity studies in MCF-7 cancer cells with a 660 nm light emitting diode.
- Full Text:
- Date Issued: 2018
The National Wellbeing Index in the isiXhosa translation: focus group discussions on how South Africans view the quality of their society
- Moller, Valerie, Roberts, Benjamin J, Zani, Dalindyebo
- Authors: Moller, Valerie , Roberts, Benjamin J , Zani, Dalindyebo
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67135 , vital:29035 , https://doi.org/10.1007/s11205-016-1481-4
- Description: publisher version , The International Wellbeing Index covers two complementary measures, the Personal Wellbeing Index (PWI) and the National Wellbeing Index (NWI). The focus group study reported here tested the understanding of the NWI when translated into isiXhosa, a language spoken by 6 million South Africans, or 16% of the country’s population. A challenge for the NWI in measuring national well-being is the tendency for meaning to get ‘lost in translation’ in the wording of the instrument, owing to the disparities that exist between levels of living in developed and developing nations. The focussed discussions with native isiXhosa speakers conveyed the different shades of meaning associated with the six domains that make up the NWI. The isiXhosa keywords for the domains of social conditions, the natural environment, national security, and management of the country’s affairs (government) were readily understood, but discussants asked for further clarification of keywords for the domains relating to the economy and business. Conversations showed up the close link between personal and national well-being: discussants drew upon their personal and parochial life experiences along with their knowledge of current affairs to evaluate the nation’s quality of life. They described the social contract between citizens and their government to create a ‘caring society’ that promotes well-being across key domains of national life. Many of the reference standards used to evaluate national well-being were ones postulated to influence personal well-being (Michalos A.C, Social Indicators Research 16(4): 347–413 1985 ). The study also pointed to a potential problem for longitudinal studies if the bipolar satisfaction scale, formerly used to measure the International Wellbeing Index’s PWI and NWI, is changed to a unipolar one. Findings from this pilot study confirm the potential of the NWI as a tool for measuring national well-being cross-culturally.
- Full Text: false
- Date Issued: 2018
- Authors: Moller, Valerie , Roberts, Benjamin J , Zani, Dalindyebo
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67135 , vital:29035 , https://doi.org/10.1007/s11205-016-1481-4
- Description: publisher version , The International Wellbeing Index covers two complementary measures, the Personal Wellbeing Index (PWI) and the National Wellbeing Index (NWI). The focus group study reported here tested the understanding of the NWI when translated into isiXhosa, a language spoken by 6 million South Africans, or 16% of the country’s population. A challenge for the NWI in measuring national well-being is the tendency for meaning to get ‘lost in translation’ in the wording of the instrument, owing to the disparities that exist between levels of living in developed and developing nations. The focussed discussions with native isiXhosa speakers conveyed the different shades of meaning associated with the six domains that make up the NWI. The isiXhosa keywords for the domains of social conditions, the natural environment, national security, and management of the country’s affairs (government) were readily understood, but discussants asked for further clarification of keywords for the domains relating to the economy and business. Conversations showed up the close link between personal and national well-being: discussants drew upon their personal and parochial life experiences along with their knowledge of current affairs to evaluate the nation’s quality of life. They described the social contract between citizens and their government to create a ‘caring society’ that promotes well-being across key domains of national life. Many of the reference standards used to evaluate national well-being were ones postulated to influence personal well-being (Michalos A.C, Social Indicators Research 16(4): 347–413 1985 ). The study also pointed to a potential problem for longitudinal studies if the bipolar satisfaction scale, formerly used to measure the International Wellbeing Index’s PWI and NWI, is changed to a unipolar one. Findings from this pilot study confirm the potential of the NWI as a tool for measuring national well-being cross-culturally.
- Full Text: false
- Date Issued: 2018
The party-state in the land occupations of Zimbabwe: the case of Shamva district
- Bhatasara, Sandra, Helliker, Kirk D
- Authors: Bhatasara, Sandra , Helliker, Kirk D
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71353 , vital:29836 , https://doi.org/10.1177/0021909616658316
- Description: There has been significant debate about the land occupations which occurred from the year 2000 in Zimbabwe, with a key controversy concerning the role of the state and ruling party (or party-state) in the occupations. This controversy, deriving from two grand narratives about the occupations, remains unresolved. A burgeoning literature exists on the Zimbabwean state’s fast-track land reform programme, which arose in the context of the occupations, but this literature is concerned mainly with post-occupation developments on fast-track farms. This article seeks to contribute to resolving the controversy surrounding the party-state and the land occupations by examining the occupations in the Shamva District of Mashonaland Central Province. The fieldwork for our Shamva study focused exclusively on the land occupations (and not on the fast-track farms) and was undertaken in May 2015. We conclude from our Shamva study that involvement by the party-state did not take on an institutionalised form but was of a personalised character entailing interventions by specific party and state actors.
- Full Text: false
- Date Issued: 2018
- Authors: Bhatasara, Sandra , Helliker, Kirk D
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71353 , vital:29836 , https://doi.org/10.1177/0021909616658316
- Description: There has been significant debate about the land occupations which occurred from the year 2000 in Zimbabwe, with a key controversy concerning the role of the state and ruling party (or party-state) in the occupations. This controversy, deriving from two grand narratives about the occupations, remains unresolved. A burgeoning literature exists on the Zimbabwean state’s fast-track land reform programme, which arose in the context of the occupations, but this literature is concerned mainly with post-occupation developments on fast-track farms. This article seeks to contribute to resolving the controversy surrounding the party-state and the land occupations by examining the occupations in the Shamva District of Mashonaland Central Province. The fieldwork for our Shamva study focused exclusively on the land occupations (and not on the fast-track farms) and was undertaken in May 2015. We conclude from our Shamva study that involvement by the party-state did not take on an institutionalised form but was of a personalised character entailing interventions by specific party and state actors.
- Full Text: false
- Date Issued: 2018
The photophysicochemical behavior of symmetric and asymmetric zinc phthalocyanines, surface assembled onto gold nanotriangles
- Dube, Edith, Nwaji, Njemuwa, Mack, John, Nyokong, Tebello
- Authors: Dube, Edith , Nwaji, Njemuwa , Mack, John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233310 , vital:50079 , xlink:href="https://doi.org/10.1039/C8NJ02746C"
- Description: The synthesis of a novel asymmetric phthalocyanine, (4-(4-(benzo[d]thiazol-2-yl)phenoxy)-2,10,17-tris(4-(2-carboxyethyl)phenoxy)phthalocyaninatol)zinc(II), complex 3, is reported. Complex 3 together with the previously reported complexes tetrakis[(benzo[d]thiazol-2-yl phenoxy)phthalocyaninato]zinc(II) (4) and 3-(4-((3,17,23-tris(4-(benzo[d]thiazol-2-yl)phenoxy)phthalocyaninatol)oxy)phenyl)propanoic acid zinc(II) (5), were linked to gold nanotriangles (AuNTs) through S–Au/Au–N self-assembly to afford the conjugates (3-AuNTs, 4-AuNTs and 5-AuNTs). The photophysicochemical behaviour of the complexes and their conjugates were studied. The asymmetric complexes 3 and 5, displayed improved triplet and singlet oxygen quantum yields compared to the symmetric complex 4, while all conjugates displayed improved triplet and singlet oxygen quantum yields compared to their respective complexes alone. The complexes and their conjugates could serve as good candidates for photodynamic therapy.
- Full Text:
- Date Issued: 2018
- Authors: Dube, Edith , Nwaji, Njemuwa , Mack, John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233310 , vital:50079 , xlink:href="https://doi.org/10.1039/C8NJ02746C"
- Description: The synthesis of a novel asymmetric phthalocyanine, (4-(4-(benzo[d]thiazol-2-yl)phenoxy)-2,10,17-tris(4-(2-carboxyethyl)phenoxy)phthalocyaninatol)zinc(II), complex 3, is reported. Complex 3 together with the previously reported complexes tetrakis[(benzo[d]thiazol-2-yl phenoxy)phthalocyaninato]zinc(II) (4) and 3-(4-((3,17,23-tris(4-(benzo[d]thiazol-2-yl)phenoxy)phthalocyaninatol)oxy)phenyl)propanoic acid zinc(II) (5), were linked to gold nanotriangles (AuNTs) through S–Au/Au–N self-assembly to afford the conjugates (3-AuNTs, 4-AuNTs and 5-AuNTs). The photophysicochemical behaviour of the complexes and their conjugates were studied. The asymmetric complexes 3 and 5, displayed improved triplet and singlet oxygen quantum yields compared to the symmetric complex 4, while all conjugates displayed improved triplet and singlet oxygen quantum yields compared to their respective complexes alone. The complexes and their conjugates could serve as good candidates for photodynamic therapy.
- Full Text:
- Date Issued: 2018
The potential use of natural resources in urban informal settlements as substitutes for financial capital during flooding emergencies
- Dalu, Mwazvita, Shackleton, Charlie M
- Authors: Dalu, Mwazvita , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179814 , vital:43191 , xlink:href="https://doi.org/10.1016/j.pce.2018.03.002"
- Description: Rapid and widespread land cover change and the subsequent loss of the buffering capacity provided by healthy ecosystems against natural hazards has resulted in increased vulnerability to natural hazards. There is an insufficient understanding of the natural resources contribution to the resilience of poor urban communities living in informal settlements and the financial implications thereof. Thus, household strategies used to recover from the October 2012 flood shock were investigated within the informal settlements of three small South African towns using questionnaires. Within the vulnerability paradigm and the sustainable livelihood framework, the study also quantified and evaluated the relative contribution of natural resources to recovery strategies and the impacts on household financial capital. We found that natural resources contributed up to 70% to recovery of households from the flood shock, most of this being to reconstruct housing structures after the flood. Factors such as household head education level, household income, kinship level, the extent of property damage and the cost associated with property rehabilitation significantly influenced the uptake of natural resources in recovery from floods, and this was variable among settlements and towns. The main findings showed that natural resources reduced household vulnerability of urban informal settlements by providing an emergency-net function that substitutes financial capital. Their inclusion in disaster management plans and responses has the potential to contribute to the sustainable livelihoods of the urban poor in the Eastern Cape, South Africa.
- Full Text:
- Date Issued: 2018
- Authors: Dalu, Mwazvita , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179814 , vital:43191 , xlink:href="https://doi.org/10.1016/j.pce.2018.03.002"
- Description: Rapid and widespread land cover change and the subsequent loss of the buffering capacity provided by healthy ecosystems against natural hazards has resulted in increased vulnerability to natural hazards. There is an insufficient understanding of the natural resources contribution to the resilience of poor urban communities living in informal settlements and the financial implications thereof. Thus, household strategies used to recover from the October 2012 flood shock were investigated within the informal settlements of three small South African towns using questionnaires. Within the vulnerability paradigm and the sustainable livelihood framework, the study also quantified and evaluated the relative contribution of natural resources to recovery strategies and the impacts on household financial capital. We found that natural resources contributed up to 70% to recovery of households from the flood shock, most of this being to reconstruct housing structures after the flood. Factors such as household head education level, household income, kinship level, the extent of property damage and the cost associated with property rehabilitation significantly influenced the uptake of natural resources in recovery from floods, and this was variable among settlements and towns. The main findings showed that natural resources reduced household vulnerability of urban informal settlements by providing an emergency-net function that substitutes financial capital. Their inclusion in disaster management plans and responses has the potential to contribute to the sustainable livelihoods of the urban poor in the Eastern Cape, South Africa.
- Full Text:
- Date Issued: 2018
The Primary Demonstration of Exciton Coupling Effects on Optical Limiting Properties of Blue Double-Decker Lanthanide Phthalocyanine Salts
- Sekhosana, Kutloano E, Nkhahle, Reitumetse, Nyokong, Tebello
- Authors: Sekhosana, Kutloano E , Nkhahle, Reitumetse , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234614 , vital:50213 , xlink:href="https://doi.org/10.1002/slct.201800597"
- Description: In this manuscript, novel green and blue sandwich-type rare-earth phthalocyanines (LnPc2) are presented. This parent green LnPc2 complex is named bis-{2(3),9(10),16(17),23(24)-tetra(4-tert-buylphenoxy) phthalocyaninato} neodymium (III) (2) and modified into blue LnPc2 complexes (3), (4) and (5) based on hexadecyltrimethylammonium ion, mononeodymium(III) diacetate and monodysprosium(III) diacetate as counter ions, respectively. These stable blue lanthanide Pc salts are highly soluble in many organic and inorganic solvents. All complexes 2, 3, 4 and 5 were studied for optical limiting for the first time using Z-scan at nanosecond regime in the visible absorption spectral wavelength (532 nm). Our studies reveal the advantage of exciton coupling in blue sandwich-type rare-earth phthalocyanines over the π-radicals (characterized by blue valence at 485 nm) in the green counterpart which are in resonance with the 532 nm wavelength for optical limiting application. Large singlet ground state to excited state absorption cross section ratios were found, particularly for complex 5 in comparison to that of complex 2.
- Full Text:
- Date Issued: 2018
- Authors: Sekhosana, Kutloano E , Nkhahle, Reitumetse , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234614 , vital:50213 , xlink:href="https://doi.org/10.1002/slct.201800597"
- Description: In this manuscript, novel green and blue sandwich-type rare-earth phthalocyanines (LnPc2) are presented. This parent green LnPc2 complex is named bis-{2(3),9(10),16(17),23(24)-tetra(4-tert-buylphenoxy) phthalocyaninato} neodymium (III) (2) and modified into blue LnPc2 complexes (3), (4) and (5) based on hexadecyltrimethylammonium ion, mononeodymium(III) diacetate and monodysprosium(III) diacetate as counter ions, respectively. These stable blue lanthanide Pc salts are highly soluble in many organic and inorganic solvents. All complexes 2, 3, 4 and 5 were studied for optical limiting for the first time using Z-scan at nanosecond regime in the visible absorption spectral wavelength (532 nm). Our studies reveal the advantage of exciton coupling in blue sandwich-type rare-earth phthalocyanines over the π-radicals (characterized by blue valence at 485 nm) in the green counterpart which are in resonance with the 532 nm wavelength for optical limiting application. Large singlet ground state to excited state absorption cross section ratios were found, particularly for complex 5 in comparison to that of complex 2.
- Full Text:
- Date Issued: 2018
The principle of complementarity and hybrid courts: the case of the Special Criminal Court for the Central African Republic
- Juma, Laurence, Chigowe, Lloyd
- Authors: Juma, Laurence , Chigowe, Lloyd
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125219 , vital:35747 , https://hdl.handle.net/10520/EJC-110b0e557f
- Description: This paper seeks to locate the place of hybrid courts in the Rome Statute’s complementarity model using the Central African Republic’s Special Courts as a case study. The introduction of the Special Courts when the International Criminal Court has already intervened in Central African Republic has raised some concern regarding the Special Courts relationship with the International Criminal Court, especially whether it may defeat the complementarity regime established under article 17 of the Rome Statute. This paper seeks to dispel this concern. It argues that the creation of the Special Criminal Court should never be perceived as an indictment to the Rome Statute principle of complementarity, but instead a useful attempt to close the impunity gap that has arisen as a result of the collapse or dysfunctionality of national criminal justice system.
- Full Text: false
- Date Issued: 2018
- Authors: Juma, Laurence , Chigowe, Lloyd
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125219 , vital:35747 , https://hdl.handle.net/10520/EJC-110b0e557f
- Description: This paper seeks to locate the place of hybrid courts in the Rome Statute’s complementarity model using the Central African Republic’s Special Courts as a case study. The introduction of the Special Courts when the International Criminal Court has already intervened in Central African Republic has raised some concern regarding the Special Courts relationship with the International Criminal Court, especially whether it may defeat the complementarity regime established under article 17 of the Rome Statute. This paper seeks to dispel this concern. It argues that the creation of the Special Criminal Court should never be perceived as an indictment to the Rome Statute principle of complementarity, but instead a useful attempt to close the impunity gap that has arisen as a result of the collapse or dysfunctionality of national criminal justice system.
- Full Text: false
- Date Issued: 2018
The production and commercialization of palm wine from Hyphaene coriacea and Phoenix reclinata in Zitundo area, southern Mozambique
- Martins, Angelina R O, Shackleton, Charlie M
- Authors: Martins, Angelina R O , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179802 , vital:43190 , xlink:href="https://doi.org/10.1016/j.sajb.2018.02.389"
- Description: In southern Mozambique a traditional wine is produced using the sap from two palm species, Hyphaene coriacea and Phoenix reclinata. Production of palm wine is one of the main livelihood activities in the Zitundo area. We examined the local production and trade of palm wine in the area. Using structured interviews we investigated the tapping activity, local management practices and the palm wine market, and assessed the incomes derived from palm wine sales and the tappers' perceptions on productivity, abundance and sales fluctuation. Tapping palms was practiced year round in five of the sixteen villages in the area and the mean number of palms tapped per day was 102 ± 52 per tapper. Tappers spent an average of 25 ± 18 h per week on tapping activities resulting in an average return to labour of R39 (± US$3) per hour. The mean, annual, net income from palm wine sales was R24,981 ± R12,094 (US$1878 ± 909) per tapper, which accounted for 85% ± 22% of the tappers' annual household income. Palm wine is a highly commercial commodity in Zitundo area, with an average commercialization index of 63% ± 23%, and is likely to help alleviate poverty in the area. Hyphaene coriacea was tapped more than Phoenix reclinata, although most tappers regard the wine from the latter to be of a better quality. The importance of palm tapping in local livelihoods and poverty alleviation needs greater acknowledgement by government and development agencies in the area, towards inclusion in sectoral development policies and conservation programmes.
- Full Text:
- Date Issued: 2018
- Authors: Martins, Angelina R O , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179802 , vital:43190 , xlink:href="https://doi.org/10.1016/j.sajb.2018.02.389"
- Description: In southern Mozambique a traditional wine is produced using the sap from two palm species, Hyphaene coriacea and Phoenix reclinata. Production of palm wine is one of the main livelihood activities in the Zitundo area. We examined the local production and trade of palm wine in the area. Using structured interviews we investigated the tapping activity, local management practices and the palm wine market, and assessed the incomes derived from palm wine sales and the tappers' perceptions on productivity, abundance and sales fluctuation. Tapping palms was practiced year round in five of the sixteen villages in the area and the mean number of palms tapped per day was 102 ± 52 per tapper. Tappers spent an average of 25 ± 18 h per week on tapping activities resulting in an average return to labour of R39 (± US$3) per hour. The mean, annual, net income from palm wine sales was R24,981 ± R12,094 (US$1878 ± 909) per tapper, which accounted for 85% ± 22% of the tappers' annual household income. Palm wine is a highly commercial commodity in Zitundo area, with an average commercialization index of 63% ± 23%, and is likely to help alleviate poverty in the area. Hyphaene coriacea was tapped more than Phoenix reclinata, although most tappers regard the wine from the latter to be of a better quality. The importance of palm tapping in local livelihoods and poverty alleviation needs greater acknowledgement by government and development agencies in the area, towards inclusion in sectoral development policies and conservation programmes.
- Full Text:
- Date Issued: 2018