'We pledge to improve the health of our entire community'
- Grant, Carolyn, Nawal, Dipty, Guntur, Sai Mala, Kumar, Manish, Chaudhuri, Indrajit, Galavotti, Christine, Mahapatra, Tanmay, Ranjan, Kunal, Kumar, Gangesh, Mohanty, Sunil, Alam, Mohammed Aftab, Das, Aritra, Jiwani, Safia
- Authors: Grant, Carolyn , Nawal, Dipty , Guntur, Sai Mala , Kumar, Manish , Chaudhuri, Indrajit , Galavotti, Christine , Mahapatra, Tanmay , Ranjan, Kunal , Kumar, Gangesh , Mohanty, Sunil , Alam, Mohammed Aftab , Das, Aritra , Jiwani, Safia
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281179 , vital:55699 , xlink:href="https://doi.org/10.1371/journal.pone.0203265"
- Description: Background: Motivation is critical to health worker performance and work quality. In Bihar, India, frontline health workers provide essential health services for the state’s poorest citizens. Yet, there is a shortfall of motivated and skilled providers and a lack of coordination between two cadres of frontline health workers and their supervisors. CARE India developed an approach aimed at improving health workers’ performance by shifting work culture and strengthening teamwork and motivation. The intervention—“Team-Based Goals and Incentives”—supported health workers to work as teams towards collective goals and rewarded success with public recognition and non-financial incentives. Methods: Thirty months after initiating the intervention, 885 health workers and 98 supervisors completed an interviewer-administered questionnaire in 38 intervention and 38 control health sub-centers in one district. The questionnaire included measures of social cohesion, teamwork attitudes, self-efficacy, job satisfaction, teamwork behaviors, equitable service delivery, taking initiative, and supervisory support. We conducted bivariate analyses to examine the impact of the intervention on these psychosocial and behavioral outcomes. Results: Results show statistically significant differences across several measures between intervention and control frontline health workers, including improved teamwork (mean = 8.8 vs. 7.3), empowerment (8.5 vs. 7.4), job satisfaction (7.1 vs. 5.99) and equitable service delivery (6.7 vs. 4.99). While fewer significant differences were found for supervisors, they reported improved teamwork (8.4 vs. 5.3), and frontline health workers reported improved fulfillment of supervisory duties by their supervisors (8.9 vs. 7.6). Both frontline health workers and supervisors found public recognition and enhanced teamwork more motivating than the non-financial incentives. Conclusions: The Team-Based Goals and Incentives model reinforces intrinsic motivation and supports improvements in the teamwork, motivation, and performance of health workers. It offers an approach to practitioners and governments for improving the work environment in a resource-constrained setting and where there are multiple cadres of health workers.
- Full Text:
- Authors: Grant, Carolyn , Nawal, Dipty , Guntur, Sai Mala , Kumar, Manish , Chaudhuri, Indrajit , Galavotti, Christine , Mahapatra, Tanmay , Ranjan, Kunal , Kumar, Gangesh , Mohanty, Sunil , Alam, Mohammed Aftab , Das, Aritra , Jiwani, Safia
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281179 , vital:55699 , xlink:href="https://doi.org/10.1371/journal.pone.0203265"
- Description: Background: Motivation is critical to health worker performance and work quality. In Bihar, India, frontline health workers provide essential health services for the state’s poorest citizens. Yet, there is a shortfall of motivated and skilled providers and a lack of coordination between two cadres of frontline health workers and their supervisors. CARE India developed an approach aimed at improving health workers’ performance by shifting work culture and strengthening teamwork and motivation. The intervention—“Team-Based Goals and Incentives”—supported health workers to work as teams towards collective goals and rewarded success with public recognition and non-financial incentives. Methods: Thirty months after initiating the intervention, 885 health workers and 98 supervisors completed an interviewer-administered questionnaire in 38 intervention and 38 control health sub-centers in one district. The questionnaire included measures of social cohesion, teamwork attitudes, self-efficacy, job satisfaction, teamwork behaviors, equitable service delivery, taking initiative, and supervisory support. We conducted bivariate analyses to examine the impact of the intervention on these psychosocial and behavioral outcomes. Results: Results show statistically significant differences across several measures between intervention and control frontline health workers, including improved teamwork (mean = 8.8 vs. 7.3), empowerment (8.5 vs. 7.4), job satisfaction (7.1 vs. 5.99) and equitable service delivery (6.7 vs. 4.99). While fewer significant differences were found for supervisors, they reported improved teamwork (8.4 vs. 5.3), and frontline health workers reported improved fulfillment of supervisory duties by their supervisors (8.9 vs. 7.6). Both frontline health workers and supervisors found public recognition and enhanced teamwork more motivating than the non-financial incentives. Conclusions: The Team-Based Goals and Incentives model reinforces intrinsic motivation and supports improvements in the teamwork, motivation, and performance of health workers. It offers an approach to practitioners and governments for improving the work environment in a resource-constrained setting and where there are multiple cadres of health workers.
- Full Text:
Informal urban fuelwood markets in South Africa in the context of socio-economic change
- Guild, J, Shackleton, Charlie M
- Authors: Guild, J , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179779 , vital:43179 , xlink:href="https://doi.org/10.1016/j.enpol.2018.03.023"
- Description: In developing countries, fuelwood is important to livelihoods and energy security because it is used for heating, cooking and can provide additional income to households through trade. The global trade in fuelwood is valued between USD 4–26 billion per annum. In South Africa, fuelwood is a widely used domestic energy source; but how that has changed with rapid urbanisation and socio-economic development over the last two decades is unknown. This study examined the presence and nature of urban fuelwood markets in 39 urban areas of the Eastern Cape and Limpopo provinces. Data were collected from 170 informal fuelwood sellers regarding the prevalence, structure, characteristics, and changes over time of the informal fuelwood markets. Over 80% of the sampled towns had an informal fuelwood market and there was a positive relationship between the number of sellers and town population size. For most sellers, the fuelwood trade was their primary occupation and the income earned was supplemented by government social grants. Sellers earned, on average, over US$9 per day. These results show that despite rapid urbanisation and socio-economic development, fuelwood remains an important domestic fuel in towns and cities of South Africa, and an income source for the urban poor.
- Full Text:
- Authors: Guild, J , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179779 , vital:43179 , xlink:href="https://doi.org/10.1016/j.enpol.2018.03.023"
- Description: In developing countries, fuelwood is important to livelihoods and energy security because it is used for heating, cooking and can provide additional income to households through trade. The global trade in fuelwood is valued between USD 4–26 billion per annum. In South Africa, fuelwood is a widely used domestic energy source; but how that has changed with rapid urbanisation and socio-economic development over the last two decades is unknown. This study examined the presence and nature of urban fuelwood markets in 39 urban areas of the Eastern Cape and Limpopo provinces. Data were collected from 170 informal fuelwood sellers regarding the prevalence, structure, characteristics, and changes over time of the informal fuelwood markets. Over 80% of the sampled towns had an informal fuelwood market and there was a positive relationship between the number of sellers and town population size. For most sellers, the fuelwood trade was their primary occupation and the income earned was supplemented by government social grants. Sellers earned, on average, over US$9 per day. These results show that despite rapid urbanisation and socio-economic development, fuelwood remains an important domestic fuel in towns and cities of South Africa, and an income source for the urban poor.
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More than just fields: Reframing deagrarianisation in landscapes and livelihoods
- Hebinck, Paul, Mtati, Nosiseko, Shackleton, Charlie M
- Authors: Hebinck, Paul , Mtati, Nosiseko , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180322 , vital:43353 , xlink:href="https://doi.org/10.1016/j.jrurstud.2018.01.004"
- Description: This paper discusses the emergent properties of deagrarianisation processes in two villages in the central Eastern Cape, South Africa. The claim of is that much of the deagrarianisation literature and debate does not acknowledge the importance of landscapes and the interaction between their constituent elements, notably people, forests, grasslands, fields, grazing lands, open spaces, built environments and homesteads, all of which contribute to shaping and, in turn, are shaped by livelihoods. Conceptualising a landscape as a spatial entity and associated assemblage of practices, discourses and history, this paper dissects the landscape in terms of land uses for residential and cultural purposes, growing, grazing and gathering. These land use categories together represent the rural domain to which the villagers are attached as a place and a home. Their use of the land is not necessarily oriented to fully exploring its productive potential. The article explores the transformation from a productive landscape to one which largely hinges on consumption. The blurring of boundaries between the formally designated land use categories signifies the transformations occurring in many of the rural areas in the former homelands of South Africa.
- Full Text:
- Authors: Hebinck, Paul , Mtati, Nosiseko , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180322 , vital:43353 , xlink:href="https://doi.org/10.1016/j.jrurstud.2018.01.004"
- Description: This paper discusses the emergent properties of deagrarianisation processes in two villages in the central Eastern Cape, South Africa. The claim of is that much of the deagrarianisation literature and debate does not acknowledge the importance of landscapes and the interaction between their constituent elements, notably people, forests, grasslands, fields, grazing lands, open spaces, built environments and homesteads, all of which contribute to shaping and, in turn, are shaped by livelihoods. Conceptualising a landscape as a spatial entity and associated assemblage of practices, discourses and history, this paper dissects the landscape in terms of land uses for residential and cultural purposes, growing, grazing and gathering. These land use categories together represent the rural domain to which the villagers are attached as a place and a home. Their use of the land is not necessarily oriented to fully exploring its productive potential. The article explores the transformation from a productive landscape to one which largely hinges on consumption. The blurring of boundaries between the formally designated land use categories signifies the transformations occurring in many of the rural areas in the former homelands of South Africa.
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Photophysicochemical behaviour and antimicrobial properties of monocarboxy Mg (II) and Al (III) phthalocyanine-magnetite conjugates
- Idowu, Mopelola A I, Xego, Solami, Arslanoglu, Yasin, Mark, John, Antunes, Edith M, Nyokong, Tebello
- Authors: Idowu, Mopelola A I , Xego, Solami , Arslanoglu, Yasin , Mark, John , Antunes, Edith M , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188205 , vital:44734 , xlink:href="https://doi.org/10.1016/j.saa.2017.12.052"
- Description: Asymmetric Mg (II) or Al (III) phthalocyanine (containing a COOH group and 3-pyridylsulfanyl units) was conjugated via an amide bond to amino functionalized magnetic nanoparticle (AIMN) to form MgPc-AIMN or AlPc-AIMN conjugate, and characterized. The photophysicochemical behaviour of the phthalocyanine–AIMN conjugates was investigated and compared to the asymmetric Pcs and to the simple mixture of Pc with AIMNs without a chemical bond, (MPc-AIMN (mixed)). The directed covalent linkage of AIMNs to the asymmetrical metallopthalocyanines afforded improvements in the singlet oxygen (ФΔ) and triplet state quantum yield (ФT) as well as singlet oxygen lifetimes for the MPcs–AIMN-linked conjugates compared to MPc-AIMN (mixed) and MPcs alone. The asymmetric phthalocyanines and their conjugates showed effective antimicrobial activity against Escherichia coli bacteria under illumination.
- Full Text:
- Authors: Idowu, Mopelola A I , Xego, Solami , Arslanoglu, Yasin , Mark, John , Antunes, Edith M , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188205 , vital:44734 , xlink:href="https://doi.org/10.1016/j.saa.2017.12.052"
- Description: Asymmetric Mg (II) or Al (III) phthalocyanine (containing a COOH group and 3-pyridylsulfanyl units) was conjugated via an amide bond to amino functionalized magnetic nanoparticle (AIMN) to form MgPc-AIMN or AlPc-AIMN conjugate, and characterized. The photophysicochemical behaviour of the phthalocyanine–AIMN conjugates was investigated and compared to the asymmetric Pcs and to the simple mixture of Pc with AIMNs without a chemical bond, (MPc-AIMN (mixed)). The directed covalent linkage of AIMNs to the asymmetrical metallopthalocyanines afforded improvements in the singlet oxygen (ФΔ) and triplet state quantum yield (ФT) as well as singlet oxygen lifetimes for the MPcs–AIMN-linked conjugates compared to MPc-AIMN (mixed) and MPcs alone. The asymmetric phthalocyanines and their conjugates showed effective antimicrobial activity against Escherichia coli bacteria under illumination.
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Wood preservation with gold hydroxyapatite system
- Ion, Rodica-Mariana, Nyokong, Tebello, Nwahara, Nnamdi, Suica-Bunghez, Ioana-Raluca, Iancu, Lorena, Teodorescu, Sofia, Dulama, Ioana D, Stirbescu, Raluca M, Gheboianu, Anca, Grigorescu, Ramona M
- Authors: Ion, Rodica-Mariana , Nyokong, Tebello , Nwahara, Nnamdi , Suica-Bunghez, Ioana-Raluca , Iancu, Lorena , Teodorescu, Sofia , Dulama, Ioana D , Stirbescu, Raluca M , Gheboianu, Anca , Grigorescu, Ramona M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187840 , vital:44702 , xlink:href="https://doi.org/10.1186/s40494-018-0202-5"
- Description: Over centuries, the external factors such as fire, low temperature, light or microbiological agents, act on the wood and induce some degradation processes, sometimes irreversible, identified by discoloration, fragility and unsightly appearance. Although there are numerous literature reports about different nanomaterials used for preservation and restoration of wood surfaces (calcium hydroxides, magnesium hydroxides, hydroxyapatite, or even organic resins as Paraloid B72), in this paper it is proposed a new system—gold hydroxyapatite (AuHAp), tested on the hazelnut wood samples (young and aged specimens), as a new solution for preservation of some wooden artifacts. This paper addresses a broad range of analytical methods: X-ray diffraction, UV–Vis spectrophotometry, Fourier transformed infrared spectroscopy, Raman spectroscopy, scanning electron microscopy with energy dispersive spectroscopy, chromatic parameters and hardness test. Also, humidity sorption/desorption measurements are used for humidity sorption and desorption evaluation. The adsorption and desorption tests determined the hydroscopic sorption properties of the wood specimens by measuring the mass of the specimens in equilibrium with air at a specific temperature and RH. All the results concluded that after the application of the new system on the hazelnut wood surface, a well distributed and uniform layer consisting from AuHAp systems with a network aspect are observed, which covers the wood vessels and fibers, filling the voids and stopping the wood weathering process, more accentuated at aged wood than at the young species.
- Full Text:
- Authors: Ion, Rodica-Mariana , Nyokong, Tebello , Nwahara, Nnamdi , Suica-Bunghez, Ioana-Raluca , Iancu, Lorena , Teodorescu, Sofia , Dulama, Ioana D , Stirbescu, Raluca M , Gheboianu, Anca , Grigorescu, Ramona M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187840 , vital:44702 , xlink:href="https://doi.org/10.1186/s40494-018-0202-5"
- Description: Over centuries, the external factors such as fire, low temperature, light or microbiological agents, act on the wood and induce some degradation processes, sometimes irreversible, identified by discoloration, fragility and unsightly appearance. Although there are numerous literature reports about different nanomaterials used for preservation and restoration of wood surfaces (calcium hydroxides, magnesium hydroxides, hydroxyapatite, or even organic resins as Paraloid B72), in this paper it is proposed a new system—gold hydroxyapatite (AuHAp), tested on the hazelnut wood samples (young and aged specimens), as a new solution for preservation of some wooden artifacts. This paper addresses a broad range of analytical methods: X-ray diffraction, UV–Vis spectrophotometry, Fourier transformed infrared spectroscopy, Raman spectroscopy, scanning electron microscopy with energy dispersive spectroscopy, chromatic parameters and hardness test. Also, humidity sorption/desorption measurements are used for humidity sorption and desorption evaluation. The adsorption and desorption tests determined the hydroscopic sorption properties of the wood specimens by measuring the mass of the specimens in equilibrium with air at a specific temperature and RH. All the results concluded that after the application of the new system on the hazelnut wood surface, a well distributed and uniform layer consisting from AuHAp systems with a network aspect are observed, which covers the wood vessels and fibers, filling the voids and stopping the wood weathering process, more accentuated at aged wood than at the young species.
- Full Text:
Revolutionary trends at the National Arts Festival 2017 (an overview)
- Authors: Krueger, Anton
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/225563 , vital:49235 , xlink:href="https://doi.org/10.1080/10137548.2017.1407025"
- Description: My 2017 Fest Everybody's festival is different. Each individual charts their own course in navigating this vast, unwieldy, multidisciplinary festival of festivals that happens every year in the Eastern Cape. Since the long running print version of the festival paper, Cue went under this year when Standard Bank withdrew funding, I wasn't officially reviewing and this freed me up to play a bit more and to see things that appealed to me, rather than having to attend shows from a sense of obligation.
- Full Text:
- Authors: Krueger, Anton
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/225563 , vital:49235 , xlink:href="https://doi.org/10.1080/10137548.2017.1407025"
- Description: My 2017 Fest Everybody's festival is different. Each individual charts their own course in navigating this vast, unwieldy, multidisciplinary festival of festivals that happens every year in the Eastern Cape. Since the long running print version of the festival paper, Cue went under this year when Standard Bank withdrew funding, I wasn't officially reviewing and this freed me up to play a bit more and to see things that appealed to me, rather than having to attend shows from a sense of obligation.
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Optical limiting properties of 3, 5-dipyrenylvinyleneBODIPY dyes at 532 nm
- Kubheka, Gugu, Sanusi, Kayode, Mack, John, Nyokong, Tebello
- Authors: Kubheka, Gugu , Sanusi, Kayode , Mack, John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/237938 , vital:50567 , xlink:href="https://doi.org/10.1016/j.saa.2017.10.021"
- Description: The optical limiting (OL) properties of 3,5-dipyrenylvinyleneBODIPY dyes that contain both electron withdrawing and donating moieties have been investigated by using the z-scan technique at 532 nm in the nanosecond pulse range. The extension of the π-conjugation at the 3,5-positions with pyrenylvinylene groups results in a ca. 200 nm red shift of the main BODIPY spectral band to ca. 700 nm, so there is relatively weak absorbance at 532 nm under ambient light conditions. Reverse saturable absorbance (RSA) profiles are observed in response to incident pulsed laser light that is consistent with a two photon absorption-assisted excited state absorption (ESA) mechanism in CH2Cl2 solution and when the dyes are embedded in poly(bisphenol carbonate A) (PBC) polymer thin films. This demonstrates that 3,5-divinyleneBODIPY dyes are potentially suitable for use in OL applications, since limiting threshold fluence (Ilim) values of below 0.95 J cm−2 are observed when thin films are prepared.
- Full Text:
- Authors: Kubheka, Gugu , Sanusi, Kayode , Mack, John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/237938 , vital:50567 , xlink:href="https://doi.org/10.1016/j.saa.2017.10.021"
- Description: The optical limiting (OL) properties of 3,5-dipyrenylvinyleneBODIPY dyes that contain both electron withdrawing and donating moieties have been investigated by using the z-scan technique at 532 nm in the nanosecond pulse range. The extension of the π-conjugation at the 3,5-positions with pyrenylvinylene groups results in a ca. 200 nm red shift of the main BODIPY spectral band to ca. 700 nm, so there is relatively weak absorbance at 532 nm under ambient light conditions. Reverse saturable absorbance (RSA) profiles are observed in response to incident pulsed laser light that is consistent with a two photon absorption-assisted excited state absorption (ESA) mechanism in CH2Cl2 solution and when the dyes are embedded in poly(bisphenol carbonate A) (PBC) polymer thin films. This demonstrates that 3,5-divinyleneBODIPY dyes are potentially suitable for use in OL applications, since limiting threshold fluence (Ilim) values of below 0.95 J cm−2 are observed when thin films are prepared.
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Think Piece. Intersectional Resonance and the Multiplicity of Being in a Polarised World
- Authors: Kulundu, Injairu
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/388037 , vital:68301 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/172212"
- Description: Understandings of collective learning and change agency often conjure up an image of a particular group or community identifying important concerns and finding the momentum to learn together to address them. In reality, gaining consensus around what issues need to be addressed is a complex process in polarised societies. It requires an attentiveness to different standpoints and experiences of the social dynamics at play, and the ways in which ecological, political, socio-economic and psychic experiences manifest themselves within different contexts, generating disparate and connected views on what is missing and what is needed to create a more just society. This paper asks questions about what it means to learn in-between and through complex and interrelated societal dynamics amongst a community of change drivers. By highlighting the individual, communal and collective learning of a diverse group of change drivers in a very polarised South Africa, we can begin to ask questions about the following: 1) how different embodied experiences or ‘a multiplicity of being’, as referred to in this paper, are essential in the pursuit of a sustainable society; and 2) why we need to learn in ways that can foster a sense of ‘intersectional resonance’ between and amongst change drivers in a polarised world.
- Full Text:
- Authors: Kulundu, Injairu
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/388037 , vital:68301 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/172212"
- Description: Understandings of collective learning and change agency often conjure up an image of a particular group or community identifying important concerns and finding the momentum to learn together to address them. In reality, gaining consensus around what issues need to be addressed is a complex process in polarised societies. It requires an attentiveness to different standpoints and experiences of the social dynamics at play, and the ways in which ecological, political, socio-economic and psychic experiences manifest themselves within different contexts, generating disparate and connected views on what is missing and what is needed to create a more just society. This paper asks questions about what it means to learn in-between and through complex and interrelated societal dynamics amongst a community of change drivers. By highlighting the individual, communal and collective learning of a diverse group of change drivers in a very polarised South Africa, we can begin to ask questions about the following: 1) how different embodied experiences or ‘a multiplicity of being’, as referred to in this paper, are essential in the pursuit of a sustainable society; and 2) why we need to learn in ways that can foster a sense of ‘intersectional resonance’ between and amongst change drivers in a polarised world.
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Electrospun 3, 5-dithienylvinyleneBODIPY embedded polystyrene nanofibers for the photocatalytic degradation of azo dyes in industrial wastewaters
- Lebechi, Augustus K, Gai, Lizhi, Shen, Zhen, Nyokong, Tebello, Mack, John
- Authors: Lebechi, Augustus K , Gai, Lizhi , Shen, Zhen , Nyokong, Tebello , Mack, John
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187679 , vital:44686 , xlink:href="https://doi.org/10.1142/S1088424618500360"
- Description: The potential utility of electrospun polystyrene (PS) nanofibers embedded with 2,6-diiodo-8-phenyl-1,7-dimethyl-3,5-di-2-thienylvinyleneBODIPY for the photocatalytic degradation of azo dyes is investigated. A comparison of the singlet oxygen quantum yield of the ππ-extended BODIPY dye in solution and in the PS nanofibers demonstrates that its photosensitizer properties are retained when it is embedded in the solid phase. The photocatalytic degradation properties of the PS nanofibers for Methyl Orange and Orange G were determined by using a Thorlabs 625 nm light emitting diode. The rate of photodegradation increases with the Orange G and Methyl Orange concentration and follows pseudo-first order kinetics at pH 6.7.
- Full Text:
- Authors: Lebechi, Augustus K , Gai, Lizhi , Shen, Zhen , Nyokong, Tebello , Mack, John
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187679 , vital:44686 , xlink:href="https://doi.org/10.1142/S1088424618500360"
- Description: The potential utility of electrospun polystyrene (PS) nanofibers embedded with 2,6-diiodo-8-phenyl-1,7-dimethyl-3,5-di-2-thienylvinyleneBODIPY for the photocatalytic degradation of azo dyes is investigated. A comparison of the singlet oxygen quantum yield of the ππ-extended BODIPY dye in solution and in the PS nanofibers demonstrates that its photosensitizer properties are retained when it is embedded in the solid phase. The photocatalytic degradation properties of the PS nanofibers for Methyl Orange and Orange G were determined by using a Thorlabs 625 nm light emitting diode. The rate of photodegradation increases with the Orange G and Methyl Orange concentration and follows pseudo-first order kinetics at pH 6.7.
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Porphyrin dimers with a bridging chiral amide-bonded benzo-moiety
- Liang, Xu, Qin, Mingfeng, Zhou, Lin, Liu, Tingting, Li, Minzhi, Mack, John, Ndebele, Nobuhle, Nyokong, Tebello, Zhu, Weihua
- Authors: Liang, Xu , Qin, Mingfeng , Zhou, Lin , Liu, Tingting , Li, Minzhi , Mack, John , Ndebele, Nobuhle , Nyokong, Tebello , Zhu, Weihua
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233433 , vital:50090 , xlink:href="https://doi.org/10.1016/j.dyepig.2018.02.043"
- Description: The facile synthesis and characterization of four porphyrin dimers which introduced stereomeric centers with chiral amide-bonded para- and meta-disubstituted benzo-moiety is reported. Trends in the electronic structures and optical and redox properties are analyzed through a comparison with theoretical calculations to explore the effect of positional isomerism of the bridging benzene rings.
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- Authors: Liang, Xu , Qin, Mingfeng , Zhou, Lin , Liu, Tingting , Li, Minzhi , Mack, John , Ndebele, Nobuhle , Nyokong, Tebello , Zhu, Weihua
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233433 , vital:50090 , xlink:href="https://doi.org/10.1016/j.dyepig.2018.02.043"
- Description: The facile synthesis and characterization of four porphyrin dimers which introduced stereomeric centers with chiral amide-bonded para- and meta-disubstituted benzo-moiety is reported. Trends in the electronic structures and optical and redox properties are analyzed through a comparison with theoretical calculations to explore the effect of positional isomerism of the bridging benzene rings.
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Rethinking urban green infrastructure and ecosystem services from the perspective of sub-Saharan African cities
- Lindley, Sarah, Pauleit, Stephan, Yeshitela, Kumelachew, Cilliers, Sarel, Shackleton, Charlie M
- Authors: Lindley, Sarah , Pauleit, Stephan , Yeshitela, Kumelachew , Cilliers, Sarel , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398357 , vital:69403 , xlink:href="https://doi.org/10.1016/j.landurbplan.2018.08.016"
- Description: Urban green infrastructure and its ecosystem services are often conceptualised in terms of a predominantly western perspective of cities and their wider social, economic and environmental challenges. However, the benefits which are derived from urban ecosystems are equally – if not more – important in the cities of the developing world. Cities in sub-Saharan Africa are well known to be facing severe pressures. Nevertheless, despite the challenges of rapid population change, high levels of poverty and seemingly chaotic urban development processes, there are also tremendous opportunities. Realising the opportunities around urban green infrastructure and its benefits requires harnessing the inherent local knowledge and community innovation associated with a multitude of inter-connected urban social-ecological systems. Such systems are a powerful driving force shaping urban realities. Associated planning regimes are frequently lambasted as being either absent, weakly enforced, corrupt or wholly inappropriate. Much of this criticism is justified. However, it must also be recognised that decision-makers are frequently working in contexts which lack the scientific foundations through which their decision-making might be made more effective and complementary to bottom-up initiatives. The paucity of research into urban ecosystems in sub-Saharan Africa and the lack of development of context-specific conceptual, theoretical and empirical foundations is a problem which must be addressed. Drawing on papers from a Special Issue centred on urban green infrastructure and urban ecosystem services in sub-Saharan Africa, we consider what concepts and frameworks are in use and what needs to be considered when framing future research. We also synthesise key messages from the Special Issue and draw together themes to help create a new research agenda for the international research community.
- Full Text:
- Authors: Lindley, Sarah , Pauleit, Stephan , Yeshitela, Kumelachew , Cilliers, Sarel , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398357 , vital:69403 , xlink:href="https://doi.org/10.1016/j.landurbplan.2018.08.016"
- Description: Urban green infrastructure and its ecosystem services are often conceptualised in terms of a predominantly western perspective of cities and their wider social, economic and environmental challenges. However, the benefits which are derived from urban ecosystems are equally – if not more – important in the cities of the developing world. Cities in sub-Saharan Africa are well known to be facing severe pressures. Nevertheless, despite the challenges of rapid population change, high levels of poverty and seemingly chaotic urban development processes, there are also tremendous opportunities. Realising the opportunities around urban green infrastructure and its benefits requires harnessing the inherent local knowledge and community innovation associated with a multitude of inter-connected urban social-ecological systems. Such systems are a powerful driving force shaping urban realities. Associated planning regimes are frequently lambasted as being either absent, weakly enforced, corrupt or wholly inappropriate. Much of this criticism is justified. However, it must also be recognised that decision-makers are frequently working in contexts which lack the scientific foundations through which their decision-making might be made more effective and complementary to bottom-up initiatives. The paucity of research into urban ecosystems in sub-Saharan Africa and the lack of development of context-specific conceptual, theoretical and empirical foundations is a problem which must be addressed. Drawing on papers from a Special Issue centred on urban green infrastructure and urban ecosystem services in sub-Saharan Africa, we consider what concepts and frameworks are in use and what needs to be considered when framing future research. We also synthesise key messages from the Special Issue and draw together themes to help create a new research agenda for the international research community.
- Full Text:
Think Piece: Pioneers as relational subjects? Probing relationality as phenomenon shaping collective learning and change agency formation
- Authors: Lotz-Sisitka, Heila
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182787 , vital:43874 , xlink:href="DOI 10.4314/sajee.v34i1.5"
- Description: This paper deliberates on how relationality is framed in collective learning and change agency formation processes, with an emphasis on green economy and renewable energy learning contexts. The paper is not focused on empirical analysis of relationality in collective learning, but rather probes the phenomenon in order to provide more carefully constituted theoretical and analytical tools for further empirical research. The paper uses references to South African and Danish cases (albeit in slightly different ways), and, through this, it sets out to provide tools for generative insights and research into a recent international policy and strategy process which is bringing national-level Green Economy Learning Assessments (GELA) into being, including one in South Africa. Central to these GELAs is the notion of participatory or relational competence, which appears to be a central feature of collective learning, although this is not empirically analysed in this paper. In case study work undertaken for the GELA in South Africa that focused on South Africa’s major renewable energy development, and in the Samsø Island renewable energy transition case in Denmark, this competence appeared to come into focus in praxis. Interestingly, however, it appeared to come into focus colloquially as a discourse on ‘pioneers’ or ‘champions’, a phenomenon noticed in both the South African and Danish contexts. This paper probes this phenomenon further, especially since it initially appears to be contradictory to the emphasis on participatory and relational competence in the GELA study framework. This is because the concept of ‘pioneer/champion’ appears to highlight individual capabilities rather than collective, relational competences. Yet, on closer inspection, it is indeed the relational competences of the pioneer/champion, who is constituted as a ‘relational subject’ with a key role to play in producing shared relational goods, that appears to be significant to the collective learning and action process. This, as argued in the paper, requires a differentiation of relationism and relational realism. This Think Piece, which thinks with both theory and praxis, therefore offers a possible framework for more detailed empirical studies on relationality in collective learning and change agency formation.
- Full Text:
- Authors: Lotz-Sisitka, Heila
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182787 , vital:43874 , xlink:href="DOI 10.4314/sajee.v34i1.5"
- Description: This paper deliberates on how relationality is framed in collective learning and change agency formation processes, with an emphasis on green economy and renewable energy learning contexts. The paper is not focused on empirical analysis of relationality in collective learning, but rather probes the phenomenon in order to provide more carefully constituted theoretical and analytical tools for further empirical research. The paper uses references to South African and Danish cases (albeit in slightly different ways), and, through this, it sets out to provide tools for generative insights and research into a recent international policy and strategy process which is bringing national-level Green Economy Learning Assessments (GELA) into being, including one in South Africa. Central to these GELAs is the notion of participatory or relational competence, which appears to be a central feature of collective learning, although this is not empirically analysed in this paper. In case study work undertaken for the GELA in South Africa that focused on South Africa’s major renewable energy development, and in the Samsø Island renewable energy transition case in Denmark, this competence appeared to come into focus in praxis. Interestingly, however, it appeared to come into focus colloquially as a discourse on ‘pioneers’ or ‘champions’, a phenomenon noticed in both the South African and Danish contexts. This paper probes this phenomenon further, especially since it initially appears to be contradictory to the emphasis on participatory and relational competence in the GELA study framework. This is because the concept of ‘pioneer/champion’ appears to highlight individual capabilities rather than collective, relational competences. Yet, on closer inspection, it is indeed the relational competences of the pioneer/champion, who is constituted as a ‘relational subject’ with a key role to play in producing shared relational goods, that appears to be significant to the collective learning and action process. This, as argued in the paper, requires a differentiation of relationism and relational realism. This Think Piece, which thinks with both theory and praxis, therefore offers a possible framework for more detailed empirical studies on relationality in collective learning and change agency formation.
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Exploring learning networks for homestead food gardening and smallholder farming
- Authors: Lotz-Sisitka, Heila
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182775 , vital:43873 , xlink:href="https://hdl.handle.net/10520/EJC-f09c3866c "
- Description: The Water Research Commission (WRC) is well known for its high quality knowledge products. The Water Utilisation in Agriculture (WUA) section has, over the years, produced valuable knowledge to guide the harvesting and conservation of rainwater to improve agricultural productivity among smallholder crop farmers and household food producers. This knowledge is useful for especially the many women farmers around the country growing crops to feed their families, and whenever possible selling excess to generate some income. However, one of the problems experienced in the field is that this knowledge does not always reach the intended audience. This is the problem that the Amanzi [Water] for Food project was engaged with.
- Full Text:
- Authors: Lotz-Sisitka, Heila
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182775 , vital:43873 , xlink:href="https://hdl.handle.net/10520/EJC-f09c3866c "
- Description: The Water Research Commission (WRC) is well known for its high quality knowledge products. The Water Utilisation in Agriculture (WUA) section has, over the years, produced valuable knowledge to guide the harvesting and conservation of rainwater to improve agricultural productivity among smallholder crop farmers and household food producers. This knowledge is useful for especially the many women farmers around the country growing crops to feed their families, and whenever possible selling excess to generate some income. However, one of the problems experienced in the field is that this knowledge does not always reach the intended audience. This is the problem that the Amanzi [Water] for Food project was engaged with.
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Towards transformative social learning on the path to 1.5 degrees
- Macintyre, Thomas, Lotz-Sisitka, Heila, Wals, Arjen E, Vogel, Coleen, Tassone, Valenina
- Authors: Macintyre, Thomas , Lotz-Sisitka, Heila , Wals, Arjen E , Vogel, Coleen , Tassone, Valenina
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182461 , vital:43832 , xlink:href="https://doi.org/10.1016/j.cosust.2017.12.003"
- Description: This paper provides insights into learning orientations and approaches that encourage change and transformation on the path to achieving the 1.5 degree C target. This literature review of the climate change and education/learning interface positions relevant literature in a heuristic tool, and reveals different learning approaches to addressing climate change. We highlight that although traditional lines of departure for achieving climate targets are usually technocratic in nature, especially if a zero emissions pathway is aimed for, there is an increasing realisation that climate issues are complex, deeply intertwined with unsustainable development and cultural change, and require collective engagement. Through considering the 1.5 degree C target as a metaphor for the fundamental changes needed in society, we argue that a wide range of learning orientations, including more inclusive and transformative social learning approaches, are needed to address the colossal challenges facing society.
- Full Text:
- Authors: Macintyre, Thomas , Lotz-Sisitka, Heila , Wals, Arjen E , Vogel, Coleen , Tassone, Valenina
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182461 , vital:43832 , xlink:href="https://doi.org/10.1016/j.cosust.2017.12.003"
- Description: This paper provides insights into learning orientations and approaches that encourage change and transformation on the path to achieving the 1.5 degree C target. This literature review of the climate change and education/learning interface positions relevant literature in a heuristic tool, and reveals different learning approaches to addressing climate change. We highlight that although traditional lines of departure for achieving climate targets are usually technocratic in nature, especially if a zero emissions pathway is aimed for, there is an increasing realisation that climate issues are complex, deeply intertwined with unsustainable development and cultural change, and require collective engagement. Through considering the 1.5 degree C target as a metaphor for the fundamental changes needed in society, we argue that a wide range of learning orientations, including more inclusive and transformative social learning approaches, are needed to address the colossal challenges facing society.
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Effect of nature of nanoparticles on the photophysicochemical properties of asymmetrically substituted Zn phthalocyanines
- Magadla, Aviwe, Oluwole, David O, Britton, Jonathan, Nyokong, Tebello
- Authors: Magadla, Aviwe , Oluwole, David O , Britton, Jonathan , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234539 , vital:50206 , xlink:href="https://doi.org/10.1016/j.ica.2018.06.043"
- Description: In this work, low symmetry Zn mono caffeic acid tri-tert butyl (1) and Zn monocarboxyphenoxy tri-(tert-butylphenoxyl) (2) phthalocyanines (Pcs) were covalently linked to amino (using glutathione, GSH, or 3-aminopropyl)triethoxysilane, APTES) functionalised nanoparticles. The nanoparticles are represented as: AgNPs-GSH, SiNPs-APTES, Fe3O4-Ag-SiNPs-APTES and Fe3O4-AgNPs-GSH). The photophysical and photochemical behaviour of the complexes 1 and 2 and their conjugates with nanoparticles were investigated in dimethyl sulfoxide. The conjugates of the Pc complexes with the NPs afforded increase in triplet quantum yields with corresponding decrease in fluorescence quantum yield compared to the Pc complexes alone. The conjugates of 1-AgNPs-GSH, 2-SiNPs-APTES and 2-Fe3O4-Ag-SiNPs-APTES showed higher singlet oxygen quantum yield values as compared to the Pc complexes alone.
- Full Text:
- Authors: Magadla, Aviwe , Oluwole, David O , Britton, Jonathan , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234539 , vital:50206 , xlink:href="https://doi.org/10.1016/j.ica.2018.06.043"
- Description: In this work, low symmetry Zn mono caffeic acid tri-tert butyl (1) and Zn monocarboxyphenoxy tri-(tert-butylphenoxyl) (2) phthalocyanines (Pcs) were covalently linked to amino (using glutathione, GSH, or 3-aminopropyl)triethoxysilane, APTES) functionalised nanoparticles. The nanoparticles are represented as: AgNPs-GSH, SiNPs-APTES, Fe3O4-Ag-SiNPs-APTES and Fe3O4-AgNPs-GSH). The photophysical and photochemical behaviour of the complexes 1 and 2 and their conjugates with nanoparticles were investigated in dimethyl sulfoxide. The conjugates of the Pc complexes with the NPs afforded increase in triplet quantum yields with corresponding decrease in fluorescence quantum yield compared to the Pc complexes alone. The conjugates of 1-AgNPs-GSH, 2-SiNPs-APTES and 2-Fe3O4-Ag-SiNPs-APTES showed higher singlet oxygen quantum yield values as compared to the Pc complexes alone.
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The use of experimental design for the development and validation of an HPLC-ECD method for the quantitation of efavirenz
- Makoni, Pedzisai A, Khamanga, Sandile M, Kasongo, Kasongo W, Walker, Roderick B
- Authors: Makoni, Pedzisai A , Khamanga, Sandile M , Kasongo, Kasongo W , Walker, Roderick B
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183556 , vital:44006 , xlink:href="https://doi.org/10.1691/ph.2018.8074"
- Description: A high performance liquid chromatography with electrochemical detection (HPLC-ECD) method for the quantitation of efavirenz (EFV) was developed, since traditional HPLC-UV methods may be inappropriate, given that EFV undergoes photolytic degradation following exposure to UV light. This work describes the use of response surface methodology (RSM) based on a central composite design (CCD) to develop a stability-indicating HPLC method with pulsed ECD in direct current (DC) mode at an applied potential difference and current of +1400 mV and 1.0 μA for the analysis of EFV. Separation of EFV and imipramine was achieved using a Nova-Pak®C18 cartridge column and a mobile phase of phosphate buffer (pH 4.5): acetonitrile (ACN) (55:45 v/v). Mobile phase pH, buffer molarity, ACN concentration and applied potential difference were investigated. The optimized method produced sharp well resolved peaks for imipramine and EFV with retention times of 3.70 and 8.89 minutes. The calibration curve was linear (R2 = 0.9979) over the range 5-70 μg/mL. Repeatability and intermediate precision ranged between 3.37 and 4.34 % RSD and 1.31 and 4.29 % RSD and accuracy between -0.80 and 4.71 % bias. The LOQ and LOD were 5.0 and 1.5 μg/mL. The method was specific for EFV and was used to analyse EFV in commercially available tablets. The HPLC-ECD method is more suitable for quantitative analysis of EFV than HPLC-UV.
- Full Text:
- Authors: Makoni, Pedzisai A , Khamanga, Sandile M , Kasongo, Kasongo W , Walker, Roderick B
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183556 , vital:44006 , xlink:href="https://doi.org/10.1691/ph.2018.8074"
- Description: A high performance liquid chromatography with electrochemical detection (HPLC-ECD) method for the quantitation of efavirenz (EFV) was developed, since traditional HPLC-UV methods may be inappropriate, given that EFV undergoes photolytic degradation following exposure to UV light. This work describes the use of response surface methodology (RSM) based on a central composite design (CCD) to develop a stability-indicating HPLC method with pulsed ECD in direct current (DC) mode at an applied potential difference and current of +1400 mV and 1.0 μA for the analysis of EFV. Separation of EFV and imipramine was achieved using a Nova-Pak®C18 cartridge column and a mobile phase of phosphate buffer (pH 4.5): acetonitrile (ACN) (55:45 v/v). Mobile phase pH, buffer molarity, ACN concentration and applied potential difference were investigated. The optimized method produced sharp well resolved peaks for imipramine and EFV with retention times of 3.70 and 8.89 minutes. The calibration curve was linear (R2 = 0.9979) over the range 5-70 μg/mL. Repeatability and intermediate precision ranged between 3.37 and 4.34 % RSD and 1.31 and 4.29 % RSD and accuracy between -0.80 and 4.71 % bias. The LOQ and LOD were 5.0 and 1.5 μg/mL. The method was specific for EFV and was used to analyse EFV in commercially available tablets. The HPLC-ECD method is more suitable for quantitative analysis of EFV than HPLC-UV.
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Incorporation of metal free and Ga 5, 10, 15, 20-tetrakis (4-bromophenyl) porphyrin into Pluronic F127-folic acid micelles
- Managa, Muthumuni, Ngoy, Bucolome P, Mafukidze, Donovan M, Nyokong, Tebello
- Authors: Managa, Muthumuni , Ngoy, Bucolome P , Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233256 , vital:50073 , xlink:href="https://doi.org/10.1016/j.jlumin.2017.09.045"
- Description: ClGa 5,10,15,20-Tetrakis (4-bromophenyl) porphyrinato (ClGaTBrPP) and its metal free derivative were successfully synthesized and incorporated into Pluronic F127 polymeric micelles that has been conjugated to folic acid (FA) to form ClGaTBrPP-F127-FA (or H2TBrPP-F127-FA). For comparison, ClGaTBrPP-F127 and H2TBrPP-F127 (without FA) were also formed. The singlet oxygen quantum yield for ClGaTBrPP-F127-FA was higher (ΦΔ = 0.44) than that of H2TBrPP-F127-FA (ΦΔ = 0.37), due to the heavy atom effect of Ga in the former which encourages intersystem crossing to the triplet state. The same applies to ClGaTBrPP-F127 (ΦΔ = 0.47) and H2TBrPP-F127 (ΦΔ = 0.41). Thus, ΦΔ values decreased in the presence of FA, but still high enough for practical application of the nanodrug system. The binding constants Kb were determined to be 1.08 × 104 M−1, 2.51 × 105 M−1, 1.52 × 103 and 2.68 × 103 for H2TBrPP+F127-FA, ClGaTBrPP+F127-FA, ClGaTBrPP-F127 and H2TBrPP-F127, respectively. The Kp values were determined in biphasic octanol and water system.
- Full Text:
- Authors: Managa, Muthumuni , Ngoy, Bucolome P , Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233256 , vital:50073 , xlink:href="https://doi.org/10.1016/j.jlumin.2017.09.045"
- Description: ClGa 5,10,15,20-Tetrakis (4-bromophenyl) porphyrinato (ClGaTBrPP) and its metal free derivative were successfully synthesized and incorporated into Pluronic F127 polymeric micelles that has been conjugated to folic acid (FA) to form ClGaTBrPP-F127-FA (or H2TBrPP-F127-FA). For comparison, ClGaTBrPP-F127 and H2TBrPP-F127 (without FA) were also formed. The singlet oxygen quantum yield for ClGaTBrPP-F127-FA was higher (ΦΔ = 0.44) than that of H2TBrPP-F127-FA (ΦΔ = 0.37), due to the heavy atom effect of Ga in the former which encourages intersystem crossing to the triplet state. The same applies to ClGaTBrPP-F127 (ΦΔ = 0.47) and H2TBrPP-F127 (ΦΔ = 0.41). Thus, ΦΔ values decreased in the presence of FA, but still high enough for practical application of the nanodrug system. The binding constants Kb were determined to be 1.08 × 104 M−1, 2.51 × 105 M−1, 1.52 × 103 and 2.68 × 103 for H2TBrPP+F127-FA, ClGaTBrPP+F127-FA, ClGaTBrPP-F127 and H2TBrPP-F127, respectively. The Kp values were determined in biphasic octanol and water system.
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Photophysical studies of graphene quantum dots-Pyrene-derivatized porphyrins conjugates when encapsulated within Pluronic F127 micelles
- Managa, Muthumuni, Achadu, Ojodomo John, Nyokong, Tebello
- Authors: Managa, Muthumuni , Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187971 , vital:44714 , xlink:href="https://doi.org/10.1016/j.dyepig.2017.09.031"
- Description: Pyrene-derivatized H2, GaCl, and Zn porphyrins were immobilized on graphene quantum dots (GQDs) to form (GQDs-H2TPrP, GQDs-GaClTPrP, and GQDs-ZnTPrP) conjugates through the π-π stacking interaction method followed by encapsulating into Pluronic F127 micelles to form (GQDs-H2TPrP + F127, GQDs-GaClTPrP + F127, and GQDs-ZnTPrP + F127). Spectroscopic evidence shows that the resultant conjugates were stable due to the strong π-π stacking interaction between the GQDs and the porphyrins. The fluorescence and singlet oxygen generating behaviour of the porphyrins were investigated following incorporation. GQDs-GaClTPrP + F127 showed highest values of the binding constant (Kb). The Stern-Volmer constant (Ksv) for GQDs-ZnTPrP + F127 were the highest compared to other porphyrins derivatives.
- Full Text:
- Authors: Managa, Muthumuni , Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187971 , vital:44714 , xlink:href="https://doi.org/10.1016/j.dyepig.2017.09.031"
- Description: Pyrene-derivatized H2, GaCl, and Zn porphyrins were immobilized on graphene quantum dots (GQDs) to form (GQDs-H2TPrP, GQDs-GaClTPrP, and GQDs-ZnTPrP) conjugates through the π-π stacking interaction method followed by encapsulating into Pluronic F127 micelles to form (GQDs-H2TPrP + F127, GQDs-GaClTPrP + F127, and GQDs-ZnTPrP + F127). Spectroscopic evidence shows that the resultant conjugates were stable due to the strong π-π stacking interaction between the GQDs and the porphyrins. The fluorescence and singlet oxygen generating behaviour of the porphyrins were investigated following incorporation. GQDs-GaClTPrP + F127 showed highest values of the binding constant (Kb). The Stern-Volmer constant (Ksv) for GQDs-ZnTPrP + F127 were the highest compared to other porphyrins derivatives.
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Photophysics and NLO properties of Ga (III) and In (III) phthalocyaninates bearing diethyleneglycol chains
- Managa, Muthumuni, Khene, Samson M, Britton, Jonathan, Martynov, Alexander G, Gorbunova, Yulia G, Tsivadze, Aslan Y, Nyokong, Tebello
- Authors: Managa, Muthumuni , Khene, Samson M , Britton, Jonathan , Martynov, Alexander G , Gorbunova, Yulia G , Tsivadze, Aslan Y , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/237822 , vital:50556 , xlink:href="https://doi.org/10.1142/S1088424618500128"
- Description: This work reports on synthesis and characterizations of Ga(III) and In(III) complexes, formed by 2,3-bis[2′′-(2′′′′-hydroxyethoxy)ethoxy]-9,10,16,17,23,24-hexa-nn-butoxy phthalocyanine (1H2) coordinating acetatoindium(III) (1InOAc) and hydroxogallium(III) (1GaOH) Photophysical properties of hydroxogallium(III) phthalocyaninate 1GaOH and acetatoindium(III) phthalocyaninate 1InOAc were studied by UV-vis, fluorescence spectroscopy and time-resolved methods. The nonlinear absorption of the complexes was studied using the Z-scan technique at 532 nm and 10 ns pulse in DMSO and in thin films formed by composite with poly(bisphenol A carbonate) — PBC. The magnitude of absorption coefficients and other nonlinear optical parameters estimated in this work showed that complex 1InOAc exhibited the strongest nonlinear optical behavior in comparison with 1GaOH in solution and a reverse tendency when embedded in PBC thin films. DFT calculations were used to rationalize these results.
- Full Text:
- Authors: Managa, Muthumuni , Khene, Samson M , Britton, Jonathan , Martynov, Alexander G , Gorbunova, Yulia G , Tsivadze, Aslan Y , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/237822 , vital:50556 , xlink:href="https://doi.org/10.1142/S1088424618500128"
- Description: This work reports on synthesis and characterizations of Ga(III) and In(III) complexes, formed by 2,3-bis[2′′-(2′′′′-hydroxyethoxy)ethoxy]-9,10,16,17,23,24-hexa-nn-butoxy phthalocyanine (1H2) coordinating acetatoindium(III) (1InOAc) and hydroxogallium(III) (1GaOH) Photophysical properties of hydroxogallium(III) phthalocyaninate 1GaOH and acetatoindium(III) phthalocyaninate 1InOAc were studied by UV-vis, fluorescence spectroscopy and time-resolved methods. The nonlinear absorption of the complexes was studied using the Z-scan technique at 532 nm and 10 ns pulse in DMSO and in thin films formed by composite with poly(bisphenol A carbonate) — PBC. The magnitude of absorption coefficients and other nonlinear optical parameters estimated in this work showed that complex 1InOAc exhibited the strongest nonlinear optical behavior in comparison with 1GaOH in solution and a reverse tendency when embedded in PBC thin films. DFT calculations were used to rationalize these results.
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Effects of Pluronic F127 micelles as delivering agents on the vitro dark toxicity and photodynamic therapy activity of carboxy and pyrene substituted porphyrins
- Managa, Muthumuni, Britton, Jonathan, Prinsloo, Earl, Nyokong, Tebello
- Authors: Managa, Muthumuni , Britton, Jonathan , Prinsloo, Earl , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234439 , vital:50196 , xlink:href="https://doi.org/10.1016/j.poly.2018.06.031"
- Description: Metal free, Zn and ClGa containing carboxyphenoxy and phenoxy groups (complexes 1) and pyrene groups (complexes 2) were synthesized and embedded into Pluronic F127 micelles (represented as F127). Dark toxicity and photodynamic therapy activities of the embedded porphyrins were successfully studied on MCF-7 breast cancer cells. Dark toxicity showed more than 80% cell viability for all complexes. It was found that 1-Zn + F127 showed better photodynamic therapy activity compared to 1-H2 + F127, and 1-ClGa + F127, corresponding to the high partition coefficient for the Zn porphyrin derivatives. The same applies to 2-Zn + F127 compared to 2-H2 + F127, 2-ClGa + F127. 1-ClGa and 1-Zn were also linked to Pluronic F127 silica nanoparticles. PDT activities for embedded 1-ClGa + F127 and 1-Zn + F127 were much higher than when linked to Pluronic silica nanoparticles (PluS NPs), showing the importance of loading of porphyrins into Pluronic F127 as a drug delivering agent rather than linking. PDT studies at the highest concentration of 60 µg/ml showed decrease in cell viability down to 15.9% for 2-Zn + F127. The Kp was determined in biphasic octanol and water system.
- Full Text:
- Authors: Managa, Muthumuni , Britton, Jonathan , Prinsloo, Earl , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234439 , vital:50196 , xlink:href="https://doi.org/10.1016/j.poly.2018.06.031"
- Description: Metal free, Zn and ClGa containing carboxyphenoxy and phenoxy groups (complexes 1) and pyrene groups (complexes 2) were synthesized and embedded into Pluronic F127 micelles (represented as F127). Dark toxicity and photodynamic therapy activities of the embedded porphyrins were successfully studied on MCF-7 breast cancer cells. Dark toxicity showed more than 80% cell viability for all complexes. It was found that 1-Zn + F127 showed better photodynamic therapy activity compared to 1-H2 + F127, and 1-ClGa + F127, corresponding to the high partition coefficient for the Zn porphyrin derivatives. The same applies to 2-Zn + F127 compared to 2-H2 + F127, 2-ClGa + F127. 1-ClGa and 1-Zn were also linked to Pluronic F127 silica nanoparticles. PDT activities for embedded 1-ClGa + F127 and 1-Zn + F127 were much higher than when linked to Pluronic silica nanoparticles (PluS NPs), showing the importance of loading of porphyrins into Pluronic F127 as a drug delivering agent rather than linking. PDT studies at the highest concentration of 60 µg/ml showed decrease in cell viability down to 15.9% for 2-Zn + F127. The Kp was determined in biphasic octanol and water system.
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