A research tool for analysing and monitoring the Extent to which Environmental issues are integrated into teachers’ lessons
- Authors: Nsubuga, Yvonne
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386447 , vital:68142 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122246"
- Description: South Africa enjoys strong policy support for the integration of environmental issues into school curricula. However, much doubt exists over the extent to which this has been converted into appropriate classroom practice at the majority of under-resourced rural schools in the country. This article reports on a study which piloted a research tool which can be used to analyse teachers’ lessons, with the aim of gaining insight into the extent to which they integrate natural resource management issues. The research tool was based on Bernstein’s concept of classification and consisted of five indicators of natural resource management integration into Life Sciences lessons. The study contributes to the design of research tools that can be used to analyse and monitor the integration of environmental issues into teachers’ lessons. It also provides some insight into the environmental content of a sample of Grade 10 Life Sciences lessons at four rural underresourced schools in the Eastern Cape.
- Full Text:
- Date Issued: 2011
- Authors: Nsubuga, Yvonne
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386447 , vital:68142 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122246"
- Description: South Africa enjoys strong policy support for the integration of environmental issues into school curricula. However, much doubt exists over the extent to which this has been converted into appropriate classroom practice at the majority of under-resourced rural schools in the country. This article reports on a study which piloted a research tool which can be used to analyse teachers’ lessons, with the aim of gaining insight into the extent to which they integrate natural resource management issues. The research tool was based on Bernstein’s concept of classification and consisted of five indicators of natural resource management integration into Life Sciences lessons. The study contributes to the design of research tools that can be used to analyse and monitor the integration of environmental issues into teachers’ lessons. It also provides some insight into the environmental content of a sample of Grade 10 Life Sciences lessons at four rural underresourced schools in the Eastern Cape.
- Full Text:
- Date Issued: 2011
Comfortably numb: Crump unveiled—a review of the 2011 Alan Crump retrospective exhibitio
- Authors: Cooper, Paul S
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147924 , vital:38685 , DOI:10.1080/00043389.2011.11877152
- Description: Writing can at times be difficult. It is not without considerable anxiety that I undertake to write this particular review. Perhaps I should offer a short qualifier: this is not strictly a review but rather a collection of ideas around the works and their arrangement, as well as my own musings and reflections on Crump. I want to pick up on what I identify to be an approach that personalises Crump as a professor, colleague and artist (we find this tone embedded throughout the accompanying exhibition catalogue). 1 I have chosen to structure this essay using a series of trigger headings, some provocative and possibly even inflammatory, others more neutral and concerned with getting to the core of what this retrospective and posthumous show is all about. All the while my thinking is to channel a sense (or lack thereof, as it may turn out) of my own experience of his work and person.
- Full Text:
- Date Issued: 2011
- Authors: Cooper, Paul S
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147924 , vital:38685 , DOI:10.1080/00043389.2011.11877152
- Description: Writing can at times be difficult. It is not without considerable anxiety that I undertake to write this particular review. Perhaps I should offer a short qualifier: this is not strictly a review but rather a collection of ideas around the works and their arrangement, as well as my own musings and reflections on Crump. I want to pick up on what I identify to be an approach that personalises Crump as a professor, colleague and artist (we find this tone embedded throughout the accompanying exhibition catalogue). 1 I have chosen to structure this essay using a series of trigger headings, some provocative and possibly even inflammatory, others more neutral and concerned with getting to the core of what this retrospective and posthumous show is all about. All the while my thinking is to channel a sense (or lack thereof, as it may turn out) of my own experience of his work and person.
- Full Text:
- Date Issued: 2011
Violence, postcolonial fiction, and the limits of sympathy:
- Authors: Marais, Mike
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143993 , vital:38301 , DOI: 10.1353/sdn.2011.0034
- Description: In this article, I consider the implications for fiction of Slavo Zizek’s argument that the violence of individual subjects is informed by ‘symbolic violence’ (1-2), that is, the distortions concomitant on languages’s constitutive, rather than merely referential, relation to the world.
- Full Text:
- Date Issued: 2011
- Authors: Marais, Mike
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143993 , vital:38301 , DOI: 10.1353/sdn.2011.0034
- Description: In this article, I consider the implications for fiction of Slavo Zizek’s argument that the violence of individual subjects is informed by ‘symbolic violence’ (1-2), that is, the distortions concomitant on languages’s constitutive, rather than merely referential, relation to the world.
- Full Text:
- Date Issued: 2011
Electrochemical, microscopic and spectroscopic characterization of benzene diamine functionalized single walled carbon nanotube-cobalt (II) tetracarboxy-phthalocyanine conjugates
- Mugadza, Tawanda, Nyokong, Tebello
- Authors: Mugadza, Tawanda , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247859 , vital:51624 , xlink:href="https://doi.org/10.1016/j.jcis.2010.10.057"
- Description: In this paper we report on the synthesis and characterization of 1,4-benzene diamine (BDA) functionalized single walled carbon nanotubes linked to cobalt (II) tetracarboxy-phthalocyanine. The characterization of the conjugate was through UV–vis, FTIR and X-ray diffraction (XRD) spectroscopies and by transmission electron microscope (TEM) and electrochemical methods. The conjugate is used for the electrochemical characterization of diuron. The catalytic rate constant for diuron was 4.4 × 103 M−1 s−1 and the apparent electron transfer rate constant was 18.5 × 10−6 cm s−1. The linear dynamic range was 1.0 × 10−5–2.0 × 10−4 M, with a sensitivity of ∼0.42 A mol−1L cm−2 and a limit of detection of 0.18 μM using the 3δ notation.
- Full Text:
- Date Issued: 2011
- Authors: Mugadza, Tawanda , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247859 , vital:51624 , xlink:href="https://doi.org/10.1016/j.jcis.2010.10.057"
- Description: In this paper we report on the synthesis and characterization of 1,4-benzene diamine (BDA) functionalized single walled carbon nanotubes linked to cobalt (II) tetracarboxy-phthalocyanine. The characterization of the conjugate was through UV–vis, FTIR and X-ray diffraction (XRD) spectroscopies and by transmission electron microscope (TEM) and electrochemical methods. The conjugate is used for the electrochemical characterization of diuron. The catalytic rate constant for diuron was 4.4 × 103 M−1 s−1 and the apparent electron transfer rate constant was 18.5 × 10−6 cm s−1. The linear dynamic range was 1.0 × 10−5–2.0 × 10−4 M, with a sensitivity of ∼0.42 A mol−1L cm−2 and a limit of detection of 0.18 μM using the 3δ notation.
- Full Text:
- Date Issued: 2011
Syntheses and electrochemical characterization of new water soluble octaarylthiosubstituted manganese phthalocyanines
- Booysen, Irvin N, Matemadombo, Fungisai, Durmus, Mahmut, Nyokong, Tebello
- Authors: Booysen, Irvin N , Matemadombo, Fungisai , Durmus, Mahmut , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247614 , vital:51600 , xlink:href="https://doi.org/10.1016/j.dyepig.2010.09.012"
- Description: This paper reports on the synthesis and characterization of new manganese phthalocyanine (MnPc) complexes: 2,3-octakis-[(2-mercaptopyridine) phthalocyaninato] acetato manganese (III) (1) and its quaternized (hence water soluble) derivative: 2,3-octakis-{[(N-methyl-2-mercaptopyridine) phthalocyaninato] acetato manganese (III)} sulphate (2). The complexes were used to form self assembled monolayers (SAMs). Voltammetry proved that both of the SAMs are well packed, strongly passivating and act as selective and efficient barriers to ion permeability. Furthermore, surface coverage studies confirmed that the MPc macrocycles adsorb onto the gold electrode as monolayers. Both MPc SAMs were successfully used as electrochemical sensors of nitrite.
- Full Text:
- Date Issued: 2011
- Authors: Booysen, Irvin N , Matemadombo, Fungisai , Durmus, Mahmut , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247614 , vital:51600 , xlink:href="https://doi.org/10.1016/j.dyepig.2010.09.012"
- Description: This paper reports on the synthesis and characterization of new manganese phthalocyanine (MnPc) complexes: 2,3-octakis-[(2-mercaptopyridine) phthalocyaninato] acetato manganese (III) (1) and its quaternized (hence water soluble) derivative: 2,3-octakis-{[(N-methyl-2-mercaptopyridine) phthalocyaninato] acetato manganese (III)} sulphate (2). The complexes were used to form self assembled monolayers (SAMs). Voltammetry proved that both of the SAMs are well packed, strongly passivating and act as selective and efficient barriers to ion permeability. Furthermore, surface coverage studies confirmed that the MPc macrocycles adsorb onto the gold electrode as monolayers. Both MPc SAMs were successfully used as electrochemical sensors of nitrite.
- Full Text:
- Date Issued: 2011
Being moved by a way the world is not
- Authors: Jones, Ward E
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275631 , vital:55064 , xlink:href="https://doi.org/10.1007/s11229-009-9522-z"
- Description: At the end of Lecture 3 of The Empirical Stance, Bas van Fraassen suggests that we see the change of view involved in scientific revolutions as being, at least in part, emotional. In this paper, I explore one plausible way of cashing out this suggestion. Someone’s emotional approval of a description of the world, I argue, thereby shows that she takes herself to have reason to take that description seriously. This is true even if she is convinced—as a scientific community is when it considers alternative theories—that this description is false, that it is not the way the world is.
- Full Text:
- Date Issued: 2011
- Authors: Jones, Ward E
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275631 , vital:55064 , xlink:href="https://doi.org/10.1007/s11229-009-9522-z"
- Description: At the end of Lecture 3 of The Empirical Stance, Bas van Fraassen suggests that we see the change of view involved in scientific revolutions as being, at least in part, emotional. In this paper, I explore one plausible way of cashing out this suggestion. Someone’s emotional approval of a description of the world, I argue, thereby shows that she takes herself to have reason to take that description seriously. This is true even if she is convinced—as a scientific community is when it considers alternative theories—that this description is false, that it is not the way the world is.
- Full Text:
- Date Issued: 2011
Water-soluble quaternized mercaptopyridine-substituted zinc-phthalocyanines
- Durmuş, Mahmut, Yaman, Hanif, Göl, Cem, Ahsen, Vefa, Nyokong, Tebello
- Authors: Durmuş, Mahmut , Yaman, Hanif , Göl, Cem , Ahsen, Vefa , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247133 , vital:51549 , xlink:href="https://doi.org/10.1016/j.dyepig.2011.02.007"
- Description: The synthesis and characterization of the new zinc phthalocyanine derivatives, tetra- (non-peripheral, 5) and octa-(peripheral, 6) substituted with 2-mercaptopyridine and their respective quaternized derivatives (8 and 9) are reported. Photochemical and photophysical properties of the new complexes are compared with those of the previously reported peripherally tetra-substituted complexes 7 and 10. The quaternized compounds exhibit excellent solubility in water, making them potential photosensitizers for use in photodynamic therapy (PDT) of cancer. Spectroscopic, aggregation, photophysical and photochemical properties of these complexes are also investigated and compared. Photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen and photodegradation quantum yield) properties of these phthalocyanine photosensitizers are very important for the assessment of these complexes as PDT agents. In this study, the effects of the position of the substituents and quaternization of the substituents on the photophysical and photochemical parameters of the zinc phthalocyanines are also reported. This study also showed that the water-soluble quaternized zinc phthalocyanines strongly bind to blood plasma proteins such as bovine serum albumin (BSA).
- Full Text:
- Date Issued: 2011
- Authors: Durmuş, Mahmut , Yaman, Hanif , Göl, Cem , Ahsen, Vefa , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247133 , vital:51549 , xlink:href="https://doi.org/10.1016/j.dyepig.2011.02.007"
- Description: The synthesis and characterization of the new zinc phthalocyanine derivatives, tetra- (non-peripheral, 5) and octa-(peripheral, 6) substituted with 2-mercaptopyridine and their respective quaternized derivatives (8 and 9) are reported. Photochemical and photophysical properties of the new complexes are compared with those of the previously reported peripherally tetra-substituted complexes 7 and 10. The quaternized compounds exhibit excellent solubility in water, making them potential photosensitizers for use in photodynamic therapy (PDT) of cancer. Spectroscopic, aggregation, photophysical and photochemical properties of these complexes are also investigated and compared. Photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen and photodegradation quantum yield) properties of these phthalocyanine photosensitizers are very important for the assessment of these complexes as PDT agents. In this study, the effects of the position of the substituents and quaternization of the substituents on the photophysical and photochemical parameters of the zinc phthalocyanines are also reported. This study also showed that the water-soluble quaternized zinc phthalocyanines strongly bind to blood plasma proteins such as bovine serum albumin (BSA).
- Full Text:
- Date Issued: 2011
Photocatalytic transformation of chlorophenols under homogeneous and heterogeneous conditions using palladium octadodecylthio phthalocyanine
- Ogunbayo, Taofeek B, Nyokong, Tebello
- Authors: Ogunbayo, Taofeek B , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/246816 , vital:51516 , xlink:href="https://doi.org/10.1016/j.molcata.2011.09.003"
- Description: Homogeneous and heterogeneous photosensitized transformations of 4-chlorophenol (4-CP) and pentachlorophenol (PCP) using palladium octadodecylthiophthalocyanine (PdODPc) were investigated. Under heterogeneous conditions, the photosensitizer was supported on functionalized single walled carbon nanotubes (SWCNTs). Homogeneous photosensitization proved to be more effective than the heterogeneous reaction in terms of percentage of transformation achieved. The kinetics of heterogeneous catalysis proved that ads-PdODPc–SWCNT–COOH (where SWCNT has been functionalized with COOH groups) was reusable for 4-CP while its activity degenerated when reused for PCP. Singlet oxygen was confirmed as playing an active role in the reactions.
- Full Text:
- Date Issued: 2011
- Authors: Ogunbayo, Taofeek B , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/246816 , vital:51516 , xlink:href="https://doi.org/10.1016/j.molcata.2011.09.003"
- Description: Homogeneous and heterogeneous photosensitized transformations of 4-chlorophenol (4-CP) and pentachlorophenol (PCP) using palladium octadodecylthiophthalocyanine (PdODPc) were investigated. Under heterogeneous conditions, the photosensitizer was supported on functionalized single walled carbon nanotubes (SWCNTs). Homogeneous photosensitization proved to be more effective than the heterogeneous reaction in terms of percentage of transformation achieved. The kinetics of heterogeneous catalysis proved that ads-PdODPc–SWCNT–COOH (where SWCNT has been functionalized with COOH groups) was reusable for 4-CP while its activity degenerated when reused for PCP. Singlet oxygen was confirmed as playing an active role in the reactions.
- Full Text:
- Date Issued: 2011
A “place in which to cry”: the place for race and a home for shame in Zoë Wicomb's Playing in the Light
- Authors: Dass, Minesh
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142588 , vital:38093 , DOI: 10.1080/1013929X.2011.602910
- Description: In Zoë Wicomb's Playing in the Light, the main character's troubled sense of identity (brought about by her parents' shameful decision to ‘play white’) is viscerally symbolised by her discomfort in her own and others' homes. In her Cape Town apartment she has nightmares about other houses. Her visits to her family home, where her elderly father lives alone, are similarly burdened by presences and memories she finds unwelcoming. And, her extended vacation to the UK, once she has discovered her family's secret, is a choice of “a place in which to cry” (Wicomb 2006: 191).
- Full Text:
- Date Issued: 2011
- Authors: Dass, Minesh
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142588 , vital:38093 , DOI: 10.1080/1013929X.2011.602910
- Description: In Zoë Wicomb's Playing in the Light, the main character's troubled sense of identity (brought about by her parents' shameful decision to ‘play white’) is viscerally symbolised by her discomfort in her own and others' homes. In her Cape Town apartment she has nightmares about other houses. Her visits to her family home, where her elderly father lives alone, are similarly burdened by presences and memories she finds unwelcoming. And, her extended vacation to the UK, once she has discovered her family's secret, is a choice of “a place in which to cry” (Wicomb 2006: 191).
- Full Text:
- Date Issued: 2011
Optimal template removal from molecularly imprinted polymers by pressurized hot water extraction
- Batlokwa, Bareki Shima, Mokgadi, Janes, Nyokong, Tebello, Torto, Nelson
- Authors: Batlokwa, Bareki Shima , Mokgadi, Janes , Nyokong, Tebello , Torto, Nelson
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247813 , vital:51620 , xlink:href="https://doi.org/10.1007/s10337-010-1884-3"
- Description: An optimal extraction method for the removal of templates from molecularly imprinted polymers (MIPs) is presented. The extraction method is based on pressurized hot water extraction (PHWE). PHWE was evaluated by application to three distinctly colored MIPs for chlorophyll (green), quercetin (yellow) and phthalocynine (dark blue) with subsequent monitoring of template removal and template bleeding by an ultraviolet spectrophotometer. The templates were washed-off and the extraction efficiency (EE) was compared to that of soxhlet and ultrasonic extraction methods. PHWE employed hot water at an optimal temperature of 220 °C, pressure of 50 bars and flow rate of 2 mL min−1 to thoroughly wash-off the respective templates from their MIPs. The EE evaluated for PHWE was over 99.6% for all the MIPs with no subsequent or minimal template bleeding (more than 0.01%). The washing procedure was simple and relatively fast as it was achieved in 70 min at the most. At 95% confidence level (n = 3), soxhlet and ultrasonic recorded EE that was not significantly different (more than 94.5% in all cases) from that of PHWE (less than 99.6% in all cases). Soxhlet and ultrasonic had washing procedures that were slower (over 18 h) and employed large quantities (400 mL) of organic solvents modified with acids. The percentage relative standard deviations (%RSD) for the EE and recovery results were less than 2.3% in all cases indicating the high reproducibility of the method. Overall, the three methods performed comparably in extracting templates. PHWE seems to be the method of choice as it employed water which poses no environmental threat.
- Full Text:
- Date Issued: 2011
- Authors: Batlokwa, Bareki Shima , Mokgadi, Janes , Nyokong, Tebello , Torto, Nelson
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247813 , vital:51620 , xlink:href="https://doi.org/10.1007/s10337-010-1884-3"
- Description: An optimal extraction method for the removal of templates from molecularly imprinted polymers (MIPs) is presented. The extraction method is based on pressurized hot water extraction (PHWE). PHWE was evaluated by application to three distinctly colored MIPs for chlorophyll (green), quercetin (yellow) and phthalocynine (dark blue) with subsequent monitoring of template removal and template bleeding by an ultraviolet spectrophotometer. The templates were washed-off and the extraction efficiency (EE) was compared to that of soxhlet and ultrasonic extraction methods. PHWE employed hot water at an optimal temperature of 220 °C, pressure of 50 bars and flow rate of 2 mL min−1 to thoroughly wash-off the respective templates from their MIPs. The EE evaluated for PHWE was over 99.6% for all the MIPs with no subsequent or minimal template bleeding (more than 0.01%). The washing procedure was simple and relatively fast as it was achieved in 70 min at the most. At 95% confidence level (n = 3), soxhlet and ultrasonic recorded EE that was not significantly different (more than 94.5% in all cases) from that of PHWE (less than 99.6% in all cases). Soxhlet and ultrasonic had washing procedures that were slower (over 18 h) and employed large quantities (400 mL) of organic solvents modified with acids. The percentage relative standard deviations (%RSD) for the EE and recovery results were less than 2.3% in all cases indicating the high reproducibility of the method. Overall, the three methods performed comparably in extracting templates. PHWE seems to be the method of choice as it employed water which poses no environmental threat.
- Full Text:
- Date Issued: 2011
The laws of Lerotholi: role and status of codified rules of custom in the kingdom of Lesotho
- Authors: Juma, Laurence
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/128810 , vital:36162 , https://heinonline.org/HOL/P?h=hein.journals/pacinlwr23ampi=94
- Description: The status of customary law in African societies is diminished by factors, most of which are generated by the machinery of the modern state. But its mantle, kept alive by neo-traditional scholarship and a commitment to multiculturalism in the post-independence era, has nevertheless sustained an active discussion on its relevance to the future of law and the general administration of justice in African states.2
- Full Text:
- Date Issued: 2011
- Authors: Juma, Laurence
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/128810 , vital:36162 , https://heinonline.org/HOL/P?h=hein.journals/pacinlwr23ampi=94
- Description: The status of customary law in African societies is diminished by factors, most of which are generated by the machinery of the modern state. But its mantle, kept alive by neo-traditional scholarship and a commitment to multiculturalism in the post-independence era, has nevertheless sustained an active discussion on its relevance to the future of law and the general administration of justice in African states.2
- Full Text:
- Date Issued: 2011
In vitro toxicity testing of zinc tetrasulfophthalocyanines in fibroblast and keratinocyte cells for the treatment of melanoma cancer by photodynamic therapy
- Maduray, Kaminee, Karsten, Alta, Odhay, Bharti, Nyokong, Tebello
- Authors: Maduray, Kaminee , Karsten, Alta , Odhay, Bharti , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247588 , vital:51597 , xlink:href="https://doi.org/10.1016/j.jphotobiol.2011.01.020"
- Description: A series of water-soluble tetrasulfonated metallophthalocyanines (MPcs) dyes have been studied to be used as a drug or photosensitizer (PS) in photodynamic therapy (PDT) for the treatment of cancers. During PDT the PS is administrated intravenously or topically to the patient before laser light at an appropriate wavelength is applied to the cancerous area to activate the PS. The activated PS will react with oxygen typically present in the cancerous tissue to generate reactive oxygen species for the destruction of the cancerous tissue. This in vitro study aimed at investigating the cytotoxic effects of different concentrations of zinc tetrasulfophthalocyanines (ZnTSPc) activated with a diode laser (λ = 672 nm) on melanoma, keratinocyte and fibroblast cells. To perform this study 3 × 104 cells/ml were seeded in 24-well plates and allowed to attach overnight, after which cells were treated with different concentrations of ZnTSPc. After 2 h, cells were irradiated with a constant light dose of 4.5 J/cm2. Post-irradiated cells were incubated for 24 h before cell viability was measured using the CellTiter-Blue Viability Assay. Data indicated high concentrations of ZnTSPc (60–100 μg/ml) in its inactive state are cytotoxic to the melanoma cancer cells. Also, results showed that photoactivated ZnTSPc (50 μg/ml) was able to reduce the cell viability of melanoma, fibroblast and keratinocyte cells to 61%, 81% and 83% respectively. At this photosensitizing concentration the efficacy the treatment light dose of 4.5 J/cm2 against other light doses of 2.5 J/cm2, 7.5 J/cm2 and 10 J/cm2 on the different cell lines were analyzed. ZnTSPc at a concentration of 50 μg/ml activated with a light dose of 4.5 J/cm2 was the most efficient for the killing of melanoma cancer cells with reduced killing effects on healthy normal skin cells in comparison to the other treatment light doses. Melanoma cancer cells after PDT with a photosensitizing concentration of 50 μg/ml and a treatment light dose of 4.5 J/cm2 showed certain apoptosis characteristics such as chromatin condensation and fragmentation of the nucleus. This concludes that low concentrations of ZnTSPc activated with the appropriate light dose can be used to induce cell death in melanoma cells with the occurrence of minimal damage to surrounding healthy tissue.
- Full Text:
- Date Issued: 2011
- Authors: Maduray, Kaminee , Karsten, Alta , Odhay, Bharti , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247588 , vital:51597 , xlink:href="https://doi.org/10.1016/j.jphotobiol.2011.01.020"
- Description: A series of water-soluble tetrasulfonated metallophthalocyanines (MPcs) dyes have been studied to be used as a drug or photosensitizer (PS) in photodynamic therapy (PDT) for the treatment of cancers. During PDT the PS is administrated intravenously or topically to the patient before laser light at an appropriate wavelength is applied to the cancerous area to activate the PS. The activated PS will react with oxygen typically present in the cancerous tissue to generate reactive oxygen species for the destruction of the cancerous tissue. This in vitro study aimed at investigating the cytotoxic effects of different concentrations of zinc tetrasulfophthalocyanines (ZnTSPc) activated with a diode laser (λ = 672 nm) on melanoma, keratinocyte and fibroblast cells. To perform this study 3 × 104 cells/ml were seeded in 24-well plates and allowed to attach overnight, after which cells were treated with different concentrations of ZnTSPc. After 2 h, cells were irradiated with a constant light dose of 4.5 J/cm2. Post-irradiated cells were incubated for 24 h before cell viability was measured using the CellTiter-Blue Viability Assay. Data indicated high concentrations of ZnTSPc (60–100 μg/ml) in its inactive state are cytotoxic to the melanoma cancer cells. Also, results showed that photoactivated ZnTSPc (50 μg/ml) was able to reduce the cell viability of melanoma, fibroblast and keratinocyte cells to 61%, 81% and 83% respectively. At this photosensitizing concentration the efficacy the treatment light dose of 4.5 J/cm2 against other light doses of 2.5 J/cm2, 7.5 J/cm2 and 10 J/cm2 on the different cell lines were analyzed. ZnTSPc at a concentration of 50 μg/ml activated with a light dose of 4.5 J/cm2 was the most efficient for the killing of melanoma cancer cells with reduced killing effects on healthy normal skin cells in comparison to the other treatment light doses. Melanoma cancer cells after PDT with a photosensitizing concentration of 50 μg/ml and a treatment light dose of 4.5 J/cm2 showed certain apoptosis characteristics such as chromatin condensation and fragmentation of the nucleus. This concludes that low concentrations of ZnTSPc activated with the appropriate light dose can be used to induce cell death in melanoma cells with the occurrence of minimal damage to surrounding healthy tissue.
- Full Text:
- Date Issued: 2011
Knowing, acting and being: Epistemological and ontological access in a Science Extended Studies course
- Authors: Ellery, Karen
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69471 , vital:29540 , https://hdl.handle.net/10520/EJC37737
- Description: Gross participation and throughput rates in higher education institutions in South Africa indicate an inequitable and poorly functioning system. This interpretive study argues for an approach that enhances epistemological and ontological access and examines how an intervention that includes an overt approach in dealing with the nature of science, coupled with student involvement in an independent research project in a Science Extended Studies course, can enhance such access to higher education study. Analysis of project outcomes and student critical reflections indicated access to scientific and academic Discourses was enhanced through: developing improved procedural and conceptual scientific knowledge; meaningful engagement with the language, norms and conventions of the Discourse; integrating everyday knowledge into more abstract scientific knowledge; awareness of the process of validation of scientific knowledge, of the limitations of science, and of the impact of science on society; and transforming personally by developing scientific discursive identity and a sense of belonging. In conclusion, it is argued that curriculum interventions that focus on epistemological and ontological aspects of learning could appropriately be used throughout the higher education science sector.
- Full Text:
- Date Issued: 2011
- Authors: Ellery, Karen
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69471 , vital:29540 , https://hdl.handle.net/10520/EJC37737
- Description: Gross participation and throughput rates in higher education institutions in South Africa indicate an inequitable and poorly functioning system. This interpretive study argues for an approach that enhances epistemological and ontological access and examines how an intervention that includes an overt approach in dealing with the nature of science, coupled with student involvement in an independent research project in a Science Extended Studies course, can enhance such access to higher education study. Analysis of project outcomes and student critical reflections indicated access to scientific and academic Discourses was enhanced through: developing improved procedural and conceptual scientific knowledge; meaningful engagement with the language, norms and conventions of the Discourse; integrating everyday knowledge into more abstract scientific knowledge; awareness of the process of validation of scientific knowledge, of the limitations of science, and of the impact of science on society; and transforming personally by developing scientific discursive identity and a sense of belonging. In conclusion, it is argued that curriculum interventions that focus on epistemological and ontological aspects of learning could appropriately be used throughout the higher education science sector.
- Full Text:
- Date Issued: 2011
Synthesis and electrochemical properties of new tetra substituted cobalt phthalocyanine complexes, and their application in electrode modification for the electrocatalysis of l-cysteine
- Erdoğmuş, Ali, Booysen, Irvin Noel, Nyokong, Tebello
- Authors: Erdoğmuş, Ali , Booysen, Irvin Noel , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247893 , vital:51627 , xlink:href="https://doi.org/10.1016/j.synthmet.2010.11.028"
- Description: This study investigates the synthesis and characterization new peripherally (β) tetra-substituted 4-(2-mercaptoquinoline phthalocyaninato) Co(II) (CoPcSHQn, 3), and 4-(2-phenoxy-4-trifluoromethylpyridine phthalocyaninato) Co(II) (CoPcOHPy, 4). These complexes were characterized by elemental analysis, IR, mass and electronic spectroscopies and electrochemical methods. Both complexes show well resolved redox peaks attributed to both ring and metal based processes. Spectroelectrochemistry was used to confirm the assignments of the redox processes. For CoPcSHQn (3): CoIPc−2/CoIPc−3 (E1/2 = −1.25 V, I), CoIIPc−2/CoIPc−2 (E1/2 = −0.57 V, II), CoIIIPc−2/CoIIPc−2 (E1/2 = +0.45 V, IV) and an irreversible process at Ep = +1.05 V vs Ag|AgCl for CoIIIPc−1/CoIIIPc−2 (V). Redox couple III at E1/2 = −0.15 V was ascribed to aggregation. In the case of CoPcOHPy (4): CoIPc−2/CoIPc−3 (E1/2 = −1.13 V, I), CoIIPc−2/CoIPc−2 (E1/2 = −0.45 V, II), CoIIIPc−2/CoIIPc−2 at E1/2 = +0.21 V (IV), and CoIIIPc−1/CoIIIPc−2 (E1/2 = +1.01 V vs Ag|AgCl, V). Again III is associated with the aggregated species. Both complexes were electrodeposited on a glassy carbon electrode (GCE). For complex 3 self-assembled monolayers was also formed. The modified (CoPc-GCE) electrodes electrocatalytically detected L-cysteine at Ep = 0.62 V (3-GCE) and 0.59 V (4-GCE) vs Ag|AgCl.
- Full Text:
- Date Issued: 2011
- Authors: Erdoğmuş, Ali , Booysen, Irvin Noel , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247893 , vital:51627 , xlink:href="https://doi.org/10.1016/j.synthmet.2010.11.028"
- Description: This study investigates the synthesis and characterization new peripherally (β) tetra-substituted 4-(2-mercaptoquinoline phthalocyaninato) Co(II) (CoPcSHQn, 3), and 4-(2-phenoxy-4-trifluoromethylpyridine phthalocyaninato) Co(II) (CoPcOHPy, 4). These complexes were characterized by elemental analysis, IR, mass and electronic spectroscopies and electrochemical methods. Both complexes show well resolved redox peaks attributed to both ring and metal based processes. Spectroelectrochemistry was used to confirm the assignments of the redox processes. For CoPcSHQn (3): CoIPc−2/CoIPc−3 (E1/2 = −1.25 V, I), CoIIPc−2/CoIPc−2 (E1/2 = −0.57 V, II), CoIIIPc−2/CoIIPc−2 (E1/2 = +0.45 V, IV) and an irreversible process at Ep = +1.05 V vs Ag|AgCl for CoIIIPc−1/CoIIIPc−2 (V). Redox couple III at E1/2 = −0.15 V was ascribed to aggregation. In the case of CoPcOHPy (4): CoIPc−2/CoIPc−3 (E1/2 = −1.13 V, I), CoIIPc−2/CoIPc−2 (E1/2 = −0.45 V, II), CoIIIPc−2/CoIIPc−2 at E1/2 = +0.21 V (IV), and CoIIIPc−1/CoIIIPc−2 (E1/2 = +1.01 V vs Ag|AgCl, V). Again III is associated with the aggregated species. Both complexes were electrodeposited on a glassy carbon electrode (GCE). For complex 3 self-assembled monolayers was also formed. The modified (CoPc-GCE) electrodes electrocatalytically detected L-cysteine at Ep = 0.62 V (3-GCE) and 0.59 V (4-GCE) vs Ag|AgCl.
- Full Text:
- Date Issued: 2011
'Amanuensis' and 'Steatopygia': the complexity of 'Telling the Tale 'in Zoë Wicomb's David's Story
- Authors: Dass, Minesh
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142599 , vital:38094 , http://dx.doi.org/10.4314/eia.v38i2.3
- Description: Two words, 'amanuensis' and 'steatopygia,' each burdened with its own history, appear in Zoë Wicomb's David's Story with a frequency that commands further consideration. This study shows that these two words are in fact narratives which reveal the tension, inherent in all historical narratives, between that which is denotative or factual and that which is connotative or fictional. Similarly, the words also form the shifting horizon from which we may see history as a narrative of the past that is always also a narrative of the present. The link between these words will ultimately show the complex, compromised role of the narrator and, perhaps, of all historians.
- Full Text:
- Date Issued: 2011
- Authors: Dass, Minesh
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142599 , vital:38094 , http://dx.doi.org/10.4314/eia.v38i2.3
- Description: Two words, 'amanuensis' and 'steatopygia,' each burdened with its own history, appear in Zoë Wicomb's David's Story with a frequency that commands further consideration. This study shows that these two words are in fact narratives which reveal the tension, inherent in all historical narratives, between that which is denotative or factual and that which is connotative or fictional. Similarly, the words also form the shifting horizon from which we may see history as a narrative of the past that is always also a narrative of the present. The link between these words will ultimately show the complex, compromised role of the narrator and, perhaps, of all historians.
- Full Text:
- Date Issued: 2011
Temperature activated ionic conductivity in gallium and indium phthalocyanines
- San, Sait Eren, Okutan, Mustafa, Nyokong, Tebello, Durmus, Mahmut, Ozturk, Birol
- Authors: San, Sait Eren , Okutan, Mustafa , Nyokong, Tebello , Durmus, Mahmut , Ozturk, Birol
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247686 , vital:51607 , xlink:href="https://doi.org/10.1016/j.poly.2010.12.047"
- Description: The effects of introducing gallium and indium metals into phthalocyanine molecules were investigated via temperature and frequency dependent dielectric spectroscopy. The dielectric properties of Ga(III) and In(III) phthalocyanine pellets were measured at frequencies from 1 kHz to 1 MHz in the temperature range 300–530 K. The temperature dependence of the real part of the dielectric constant suggested that these compounds exhibit semiconductor behavior. The activation energy values were calculated from the Arrhenius plots at different frequencies. A distinct transition in these plots indicated the activation of ionic conductivity at higher temperatures.
- Full Text:
- Date Issued: 2011
- Authors: San, Sait Eren , Okutan, Mustafa , Nyokong, Tebello , Durmus, Mahmut , Ozturk, Birol
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247686 , vital:51607 , xlink:href="https://doi.org/10.1016/j.poly.2010.12.047"
- Description: The effects of introducing gallium and indium metals into phthalocyanine molecules were investigated via temperature and frequency dependent dielectric spectroscopy. The dielectric properties of Ga(III) and In(III) phthalocyanine pellets were measured at frequencies from 1 kHz to 1 MHz in the temperature range 300–530 K. The temperature dependence of the real part of the dielectric constant suggested that these compounds exhibit semiconductor behavior. The activation energy values were calculated from the Arrhenius plots at different frequencies. A distinct transition in these plots indicated the activation of ionic conductivity at higher temperatures.
- Full Text:
- Date Issued: 2011
Syntheses, electrochemical and spectroelectrochemical properties of novel ball-type and mononuclear Co (II) phthalocyanines substituted at the peripheral and non-peripheral positions with binaphthol groups
- Canlıca, Mevlüde, Booysen, Irvin Noel, Nyokong, Tebello
- Authors: Canlıca, Mevlüde , Booysen, Irvin Noel , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247837 , vital:51622 , xlink:href="https://doi.org/10.1016/j.poly.2010.11.017"
- Description: Mononuclear cobalt phthalocyanine (CoPc) substituted at the non-peripheral 8 and peripheral positions 9 with 1,1′-binaphthyl-8,8′-diol and ball-type dinuclear Co2Pc2 substituted at the non-peripheral 10 and peripheral 11 positions with the same substituent are reported. The complexes with 1,1′-binaphthol-bridges were prepared from the corresponding phthalonitriles 4–7. The effects of the position of substituent on spectral, electrochemical and spectroelectrochemical properties of these complexes were also explored. The mononuclear complexes 8 and 9 exhibited one metal reduction, one ring reduction and one ring oxidation. The redox properties of the ball-type complexes 10 and 11 exhibited two reduction processes assigned to [(CoIPc−2)2]2−/[(CoIPc−3)2]4− (I), (CoIIPc−2)2/[(CoIPc−2)2]2− (II) and one oxidation process assigned to [(CoIIIPc−2)2]2+/CoIIPc−2)2 (III). The ball-type complexes are much easier to oxidize and more difficult to reduce than the corresponding monomers 8 and 9.
- Full Text:
- Date Issued: 2011
- Authors: Canlıca, Mevlüde , Booysen, Irvin Noel , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247837 , vital:51622 , xlink:href="https://doi.org/10.1016/j.poly.2010.11.017"
- Description: Mononuclear cobalt phthalocyanine (CoPc) substituted at the non-peripheral 8 and peripheral positions 9 with 1,1′-binaphthyl-8,8′-diol and ball-type dinuclear Co2Pc2 substituted at the non-peripheral 10 and peripheral 11 positions with the same substituent are reported. The complexes with 1,1′-binaphthol-bridges were prepared from the corresponding phthalonitriles 4–7. The effects of the position of substituent on spectral, electrochemical and spectroelectrochemical properties of these complexes were also explored. The mononuclear complexes 8 and 9 exhibited one metal reduction, one ring reduction and one ring oxidation. The redox properties of the ball-type complexes 10 and 11 exhibited two reduction processes assigned to [(CoIPc−2)2]2−/[(CoIPc−3)2]4− (I), (CoIIPc−2)2/[(CoIPc−2)2]2− (II) and one oxidation process assigned to [(CoIIIPc−2)2]2+/CoIIPc−2)2 (III). The ball-type complexes are much easier to oxidize and more difficult to reduce than the corresponding monomers 8 and 9.
- Full Text:
- Date Issued: 2011
Privatisation, human rights and security: reflections on the draft international convention on regulation, oversight and monitoring of private military and security companies
- Authors: Juma, Laurence
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/128800 , vital:36160 , http://dx.doi.org/10.4314/ldd.v15i1.3
- Description: Efforts to establish regulatory frameworks for private military/security companies (PMSCs), driven by public security concerns as well as private interests of the companies themselves, have yielded a number of soft law instruments. Unfortunately, most of these instruments are conditioned by the underlying interests of their promulgators and have therefore failed to establish universally acceptable regulatory standards.
- Full Text:
- Date Issued: 2011
- Authors: Juma, Laurence
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/128800 , vital:36160 , http://dx.doi.org/10.4314/ldd.v15i1.3
- Description: Efforts to establish regulatory frameworks for private military/security companies (PMSCs), driven by public security concerns as well as private interests of the companies themselves, have yielded a number of soft law instruments. Unfortunately, most of these instruments are conditioned by the underlying interests of their promulgators and have therefore failed to establish universally acceptable regulatory standards.
- Full Text:
- Date Issued: 2011
In service to the law: Alastair James Kerr SC
- Authors: Glover, Graham B
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70658 , vital:29686 , https://hdl.handle.net/10520/EJC53959
- Description: Professor Alastair James Kerr SC passed away at Settlers Hospital in Grahamstown on the 29th of September 2010. He was eighty-eight years of age. Ironically, his death occurred at the time that the third part of the 2010 SALJ appeared in print, containing a tribute to one of the other great writers on South African contract law, Professor Richard (Dick) Christie, who had passed away earlier in the year (see A J G Lang 'Professor Richard Hunter Christie: A memorial tribute' (2010) 127 SALJ 414). 2010 may have been a momentous year in South Africa for many reasons, but the deaths of these two men in the same year has left the landscape of our contract law irrevocably changed, even though their ideas will live on through their published works.
- Full Text: false
- Date Issued: 2011
- Authors: Glover, Graham B
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70658 , vital:29686 , https://hdl.handle.net/10520/EJC53959
- Description: Professor Alastair James Kerr SC passed away at Settlers Hospital in Grahamstown on the 29th of September 2010. He was eighty-eight years of age. Ironically, his death occurred at the time that the third part of the 2010 SALJ appeared in print, containing a tribute to one of the other great writers on South African contract law, Professor Richard (Dick) Christie, who had passed away earlier in the year (see A J G Lang 'Professor Richard Hunter Christie: A memorial tribute' (2010) 127 SALJ 414). 2010 may have been a momentous year in South Africa for many reasons, but the deaths of these two men in the same year has left the landscape of our contract law irrevocably changed, even though their ideas will live on through their published works.
- Full Text: false
- Date Issued: 2011
The problems of proving actual or apparent bias: an analysis of contemporary developments in South Africa
- Okpaluba, Chuks, Juma, Laurence
- Authors: Okpaluba, Chuks , Juma, Laurence
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127498 , vital:36017 , https://doi.org/10.17159/1727-3781/2011/v14i7a2616
- Description: This article takes a critical look at the divergent approaches of courts in constructing the meaning of actual and apparent bias in adjudicative contexts. It argues that while proving actual bias on the part of an adjudicator may not always be easy and parties often revert to apprehended bias, an allegation of bias in any adjudication process is a matter that courts take very seriously. This notwithstanding, the courts have failed to consistently demarcate the necessary elements and threshold of proof that complainants must overcome to secure a successful challenge of decisions based on adjudicative impartiality. Upon critical evaluation of the decisions on the subject so far rendered, this article suggests that the pattern which has seemingly emerged is that which weighs the allegations of bias against the presumption of impartiality and the requirements of the double reasonableness test.
- Full Text:
- Date Issued: 2011
- Authors: Okpaluba, Chuks , Juma, Laurence
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127498 , vital:36017 , https://doi.org/10.17159/1727-3781/2011/v14i7a2616
- Description: This article takes a critical look at the divergent approaches of courts in constructing the meaning of actual and apparent bias in adjudicative contexts. It argues that while proving actual bias on the part of an adjudicator may not always be easy and parties often revert to apprehended bias, an allegation of bias in any adjudication process is a matter that courts take very seriously. This notwithstanding, the courts have failed to consistently demarcate the necessary elements and threshold of proof that complainants must overcome to secure a successful challenge of decisions based on adjudicative impartiality. Upon critical evaluation of the decisions on the subject so far rendered, this article suggests that the pattern which has seemingly emerged is that which weighs the allegations of bias against the presumption of impartiality and the requirements of the double reasonableness test.
- Full Text:
- Date Issued: 2011