Targeting conserved pathways as a strategy for novel drug development: disabling the cellular stress response:
- Edkins, Adrienne L, Blatch, Gregory L
- Authors: Edkins, Adrienne L , Blatch, Gregory L
- Date: 2012
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/165129 , vital:41211 , ISBN 978-3-642-28174-7 , DOI: 10.1007/978-3-642-28175-4_4
- Description: The ability to respond to and cope with stress at a molecular level is essential for cell survival. The stress response is conserved across organisms by the expression of a group of molecular chaperones known as heat shock proteins (HSP). HSP are ubiquitous and highly conserved proteins that regulate cellular protein homeostasis and trafficking under physiological and stressful conditions, including diseases such as cancer and malaria. HSP are good drug targets for the treatment of human diseases, as the significant functional and structural data available suggest that they are essential for cell survival and that, despite conservation across species, there are biophysical and biochemical differences between HSP in normal and disease states that allow HSP to be selectively targeted. In this chapter, we review the international status of this area of research and highlight progress by us and other African researchers towards the characterisation and targeting of HSP from humans and parasites from Plasmodium and Trypanosoma as drug targets.
- Full Text:
- Date Issued: 2012
- Authors: Edkins, Adrienne L , Blatch, Gregory L
- Date: 2012
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/165129 , vital:41211 , ISBN 978-3-642-28174-7 , DOI: 10.1007/978-3-642-28175-4_4
- Description: The ability to respond to and cope with stress at a molecular level is essential for cell survival. The stress response is conserved across organisms by the expression of a group of molecular chaperones known as heat shock proteins (HSP). HSP are ubiquitous and highly conserved proteins that regulate cellular protein homeostasis and trafficking under physiological and stressful conditions, including diseases such as cancer and malaria. HSP are good drug targets for the treatment of human diseases, as the significant functional and structural data available suggest that they are essential for cell survival and that, despite conservation across species, there are biophysical and biochemical differences between HSP in normal and disease states that allow HSP to be selectively targeted. In this chapter, we review the international status of this area of research and highlight progress by us and other African researchers towards the characterisation and targeting of HSP from humans and parasites from Plasmodium and Trypanosoma as drug targets.
- Full Text:
- Date Issued: 2012
Differential regulation of monocyte cytokine release by αV and β2 integrins that bind CD23:
- Edkins, Adrienne L, Borland, Gillian, Acharya, Mridu, Cogdell, Richard, Ozanne, Bradford W, Cushley, William
- Authors: Edkins, Adrienne L , Borland, Gillian , Acharya, Mridu , Cogdell, Richard , Ozanne, Bradford W , Cushley, William
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165153 , vital:41213 , DOI: 10.1111/j.1365-2567.2012.03576.x
- Description: The human soluble CD23 (sCD23) protein displays highly pleiotropic cytokine‐like activity. Monocytic cells express the sCD23‐binding integrins αVβ3, αVβ5, αMβ2 and αXβ2, but it is unclear which of these four integrins most acutely regulates sCD23‐driven cytokine release. The hypothesis that ligation of different sCD23‐binding integrins promoted release of distinct subsets of cytokines was tested. Lipopolysaccharide (LPS) and sCD23 promoted release of distinct groups of cytokines from the THP‐1 model cell line.
- Full Text:
- Date Issued: 2012
- Authors: Edkins, Adrienne L , Borland, Gillian , Acharya, Mridu , Cogdell, Richard , Ozanne, Bradford W , Cushley, William
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165153 , vital:41213 , DOI: 10.1111/j.1365-2567.2012.03576.x
- Description: The human soluble CD23 (sCD23) protein displays highly pleiotropic cytokine‐like activity. Monocytic cells express the sCD23‐binding integrins αVβ3, αVβ5, αMβ2 and αXβ2, but it is unclear which of these four integrins most acutely regulates sCD23‐driven cytokine release. The hypothesis that ligation of different sCD23‐binding integrins promoted release of distinct subsets of cytokines was tested. Lipopolysaccharide (LPS) and sCD23 promoted release of distinct groups of cytokines from the THP‐1 model cell line.
- Full Text:
- Date Issued: 2012
Peat formation in the context of the development of the Mkuze floodplain on the coastal plain of Maputaland, South Africa:
- Ellery, William F N, Grenfell, Suzanne E, Grenfell, Michael C, Humphries, M S, Barnes, K, Dahlberg, S, Kindness, A
- Authors: Ellery, William F N , Grenfell, Suzanne E , Grenfell, Michael C , Humphries, M S , Barnes, K , Dahlberg, S , Kindness, A
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144354 , vital:38338 , DOI: 10.1016/j.geomorph.2011.11.009
- Description: This paper examines the geomorphological and sedimentological development of blocked-valley lakes in the Mkuze floodplain on the coastal plain of Maputaland, northern KwaZulu-Natal, South Africa. Blocked tributary valley lakes north of the floodplain become progressively shorter, broader, and less linear toward the eastern (downstream) end of the east–west oriented Mkuze floodplain. Clastic sediment forms surface sedimentary fill in tributary valleys in the west, while peat predominates tributary valley fill in the east. Two contrasting adjacent tributary valleys were examined, the more western Yengweni dominated by clastic sediment at the surface, and the more eastern Totweni with peat.
- Full Text:
- Date Issued: 2012
- Authors: Ellery, William F N , Grenfell, Suzanne E , Grenfell, Michael C , Humphries, M S , Barnes, K , Dahlberg, S , Kindness, A
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144354 , vital:38338 , DOI: 10.1016/j.geomorph.2011.11.009
- Description: This paper examines the geomorphological and sedimentological development of blocked-valley lakes in the Mkuze floodplain on the coastal plain of Maputaland, northern KwaZulu-Natal, South Africa. Blocked tributary valley lakes north of the floodplain become progressively shorter, broader, and less linear toward the eastern (downstream) end of the east–west oriented Mkuze floodplain. Clastic sediment forms surface sedimentary fill in tributary valleys in the west, while peat predominates tributary valley fill in the east. Two contrasting adjacent tributary valleys were examined, the more western Yengweni dominated by clastic sediment at the surface, and the more eastern Totweni with peat.
- Full Text:
- Date Issued: 2012
Firm age, collateral value, and access to debt financing in an emerging economy: evidence from South Africa
- Authors: Ezeoha,Abel , Botha, Ferdi
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/396060 , vital:69147 , xlink:href="https://hdl.handle.net/10520/EJC31367"
- Description: This paper applies the Blundell and Bond system generalised method of moments (GMM) two-step estimator to examine the impact of age and collateral value on debt financing, using a panel of 177 non-financial companies listed on the Johannesburg Stock Exchange over the period 1999 to 2009. The results show that South African firms have target leverage ratios and adjust their capital structures from time to time to achieve their respective targets, that the relationship between firm age and debt financing is non-monotonic, and that firms with higher collateral value are likely to face fewer constraints on borrowing and therefore have greater access to medium-term and long-term debts. Robustness tests also reveal that during start-up and maturity stages, a firm's access to debt markets is significantly influenced by investments in assets that are acceptable to external creditors as collateral. These findings suggest that debt financing policies could be more critical for firms in the start-up and maturity stages.
- Full Text:
- Date Issued: 2012
- Authors: Ezeoha,Abel , Botha, Ferdi
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/396060 , vital:69147 , xlink:href="https://hdl.handle.net/10520/EJC31367"
- Description: This paper applies the Blundell and Bond system generalised method of moments (GMM) two-step estimator to examine the impact of age and collateral value on debt financing, using a panel of 177 non-financial companies listed on the Johannesburg Stock Exchange over the period 1999 to 2009. The results show that South African firms have target leverage ratios and adjust their capital structures from time to time to achieve their respective targets, that the relationship between firm age and debt financing is non-monotonic, and that firms with higher collateral value are likely to face fewer constraints on borrowing and therefore have greater access to medium-term and long-term debts. Robustness tests also reveal that during start-up and maturity stages, a firm's access to debt markets is significantly influenced by investments in assets that are acceptable to external creditors as collateral. These findings suggest that debt financing policies could be more critical for firms in the start-up and maturity stages.
- Full Text:
- Date Issued: 2012
Unquenched fluorescence lifetime for β-phenylthio substituted zinc phthalocyanine upon conjugation to gold nanoparticles
- Forteath, Shaun, Antunes, Edith M, Chidawanyika, Wadzanai J U, Nyokong, Tebello
- Authors: Forteath, Shaun , Antunes, Edith M , Chidawanyika, Wadzanai J U , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/245774 , vital:51404 , xlink:href="https://doi.org/10.1016/j.poly.2011.12.015"
- Description: Photoinduced processes in phthalocyanine-functionalized gold nanoparticles have been investigated by spectroscopic measurements. The zinc phthalocyanine used contained four phenylthio peripheral substituents (ZnPc(SPh)4). The conjugates formed are represented as ZnPc(SPh)4–AuNP. The absorption spectrum of the ZnPc(SPh)4–AuNP shows a broadening of the phthalocyanine Q-band absorption, probably due to a tight packing of the phthalocyanines on the gold nanoparticle surface. For the attached phthalocyanines, the two fluorescence lifetimes obtained by time-correlated single photon counting (TCSPC) were determined to be both longer and shorter than that of the free Pc. The fluorescence lifetimes were resolved using time resolved fluorescence spectroscopy (TRES).
- Full Text:
- Date Issued: 2012
- Authors: Forteath, Shaun , Antunes, Edith M , Chidawanyika, Wadzanai J U , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/245774 , vital:51404 , xlink:href="https://doi.org/10.1016/j.poly.2011.12.015"
- Description: Photoinduced processes in phthalocyanine-functionalized gold nanoparticles have been investigated by spectroscopic measurements. The zinc phthalocyanine used contained four phenylthio peripheral substituents (ZnPc(SPh)4). The conjugates formed are represented as ZnPc(SPh)4–AuNP. The absorption spectrum of the ZnPc(SPh)4–AuNP shows a broadening of the phthalocyanine Q-band absorption, probably due to a tight packing of the phthalocyanines on the gold nanoparticle surface. For the attached phthalocyanines, the two fluorescence lifetimes obtained by time-correlated single photon counting (TCSPC) were determined to be both longer and shorter than that of the free Pc. The fluorescence lifetimes were resolved using time resolved fluorescence spectroscopy (TRES).
- Full Text:
- Date Issued: 2012
Synthesis and photophysical behavior of a novel zinc phthalocyanine containing a single carboxylic acid and three phenylthio substituents
- Forteath, Shaun, Antunes, Edith M, Chidawanyika, Wadzanai J U, Nyokong, Tebello
- Authors: Forteath, Shaun , Antunes, Edith M , Chidawanyika, Wadzanai J U , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243207 , vital:51127 , xlink:href="https://doi.org/10.1016/j.jlumin.2012.03.050"
- Description: Zinc 2, (3)-tri-(phenylthio)-2, (3)-carboxy phthalocyanine (ZnPc(COOH)(SPh)3), zinc 2, (3)-tetra-(phenylthio) phthalocyanine (ZnPc(SPh)4) and 2, (3)-tetra-(phenylthio) phthalocyanine (H2Pc(SPh)4) were synthesized and their photophysical behavior were compared with those of a number of zinc phthalocyanine (ZnPc) derivatives. ZnPc(COOH)(SPh)3 and ZnPc(SPh)4 had similar fluorescence (ΦF=0.14) and triplet state (ΦT=0.65) quantum yields in dimethylsulfoxide, hence showing no effects of the replacement of one of the phenylthio groups with a carboxylic acid group. ZnPc(COOH)(SPh)3 displayed a slightly shorter triplet lifetime (τT=331 μs) than ZnPc (τT=350 μs) in DMSO, but within the range of ZnPc derivatives. The triplet lifetime for ZnPc(COOH)(SPh)3 is much longer than for the symmetrical derivative (ZnPc(SPh)4) with τT=149 μs in DMSO.
- Full Text:
- Date Issued: 2012
- Authors: Forteath, Shaun , Antunes, Edith M , Chidawanyika, Wadzanai J U , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243207 , vital:51127 , xlink:href="https://doi.org/10.1016/j.jlumin.2012.03.050"
- Description: Zinc 2, (3)-tri-(phenylthio)-2, (3)-carboxy phthalocyanine (ZnPc(COOH)(SPh)3), zinc 2, (3)-tetra-(phenylthio) phthalocyanine (ZnPc(SPh)4) and 2, (3)-tetra-(phenylthio) phthalocyanine (H2Pc(SPh)4) were synthesized and their photophysical behavior were compared with those of a number of zinc phthalocyanine (ZnPc) derivatives. ZnPc(COOH)(SPh)3 and ZnPc(SPh)4 had similar fluorescence (ΦF=0.14) and triplet state (ΦT=0.65) quantum yields in dimethylsulfoxide, hence showing no effects of the replacement of one of the phenylthio groups with a carboxylic acid group. ZnPc(COOH)(SPh)3 displayed a slightly shorter triplet lifetime (τT=331 μs) than ZnPc (τT=350 μs) in DMSO, but within the range of ZnPc derivatives. The triplet lifetime for ZnPc(COOH)(SPh)3 is much longer than for the symmetrical derivative (ZnPc(SPh)4) with τT=149 μs in DMSO.
- Full Text:
- Date Issued: 2012
Municipal commonage: an undervalued national resource
- Gambiza, James, Shackleton, Charlie M, Davenport, N, Atkinson, D, Hoffman, M T, Martens, C, Puttick, J, De Groot, W
- Authors: Gambiza, James , Shackleton, Charlie M , Davenport, N , Atkinson, D , Hoffman, M T , Martens, C , Puttick, J , De Groot, W
- Date: 2012
- Subjects: Land reform -- South Africa Land use -- South Africa South Africa -- Social conditions
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/49969 , vital:25947
- Description: This policy brief will highlight the importance of municipal commonage in enhancing livelihoods of poor urban families. This will be followed by an overview of the role of municipal commonage in the land reform programme. Current challenges in securing benefits from municipal commonages are then outlined. Policy considerations to optimise benefits from commonages conclude the policy brief.
- Full Text:
- Date Issued: 2012
- Authors: Gambiza, James , Shackleton, Charlie M , Davenport, N , Atkinson, D , Hoffman, M T , Martens, C , Puttick, J , De Groot, W
- Date: 2012
- Subjects: Land reform -- South Africa Land use -- South Africa South Africa -- Social conditions
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/49969 , vital:25947
- Description: This policy brief will highlight the importance of municipal commonage in enhancing livelihoods of poor urban families. This will be followed by an overview of the role of municipal commonage in the land reform programme. Current challenges in securing benefits from municipal commonages are then outlined. Policy considerations to optimise benefits from commonages conclude the policy brief.
- Full Text:
- Date Issued: 2012
Troubling White Englishness in South Africa:
- Authors: Garman, Anthea
- Date: 2012
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/159756 , vital:40340 , ISBN 978-1-84888-105-1
- Description: To be white in Africa is to be part of a minority - but a very powerful minority. To be white in South Africa is to be implicated and complicit in historical dispossession and disenfranchisement. However, in post-apartheid South Africa, whiteness is no longer the invisible condition of the default human being, a condition to which all other humans must aspire. In fact, to be white is suddenly to be very visibly Other to the black African majority who are increasingly shaping the social landscape in ways that undermine the trajectories of both the colonial project and the apartheid project in this country.
- Full Text:
- Date Issued: 2012
- Authors: Garman, Anthea
- Date: 2012
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/159756 , vital:40340 , ISBN 978-1-84888-105-1
- Description: To be white in Africa is to be part of a minority - but a very powerful minority. To be white in South Africa is to be implicated and complicit in historical dispossession and disenfranchisement. However, in post-apartheid South Africa, whiteness is no longer the invisible condition of the default human being, a condition to which all other humans must aspire. In fact, to be white is suddenly to be very visibly Other to the black African majority who are increasingly shaping the social landscape in ways that undermine the trajectories of both the colonial project and the apartheid project in this country.
- Full Text:
- Date Issued: 2012
Juta and Co Ltd and the South African Law Journal: a milestone
- Authors: Glover, Graham B
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70539 , vital:29673 , https://hdl.handle.net/10520/EJC54018
- Description: It might be said that the relationship between a journal and its publisher is something like an arranged marriage: it is cultural rather than romantic, and it is more of a business deal carefully considered by those in charge of both sets of parties with quiet aspirations of a solid future than about the passion and emotion of the wedding. There is much that is controversial about the social construct of an arranged marriage, but the relationship between the South African Law Journal (SALJ) and Juta and Company Ltd (to be referred to hereafter by its more common sobriquet in the legal profession: 'Juta') does seem to give credence to one of the most popular psychologies about the institution: that very often the relationship, a little uncertain at the start, grows stronger and more secure over time. The year 2011 marked the centenary of the publication of the SALJ by Juta: an exceptional anniversary. This is not a time to review the history of the relationship between Juta, the SALJ, and its various editors. This task has been carried out several times by Ellison Kahn in his inimitable style (see 'Fifty years of the Journal under Union' (1960) 77 SALJ 162; 'The birth and life of the South African Law Journal' (1983) 100 SALJ 594; 'Foreword' to Patricia Cobbledick and Mervyn Dendy The South African Law Journal Cumulative Index 1973-1997 (1997); 'Farewell! Fifty years' hard work comes to an end' (1999) 116 SALJ 691; 'Speech at the Juta Dinner at the South African Law Journal Jubilee Conference' (2004) 121 SALJ 271). But a short commemorative tribute seems apt to commemorate the liaison between the two parties.
- Full Text: false
- Date Issued: 2012
- Authors: Glover, Graham B
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70539 , vital:29673 , https://hdl.handle.net/10520/EJC54018
- Description: It might be said that the relationship between a journal and its publisher is something like an arranged marriage: it is cultural rather than romantic, and it is more of a business deal carefully considered by those in charge of both sets of parties with quiet aspirations of a solid future than about the passion and emotion of the wedding. There is much that is controversial about the social construct of an arranged marriage, but the relationship between the South African Law Journal (SALJ) and Juta and Company Ltd (to be referred to hereafter by its more common sobriquet in the legal profession: 'Juta') does seem to give credence to one of the most popular psychologies about the institution: that very often the relationship, a little uncertain at the start, grows stronger and more secure over time. The year 2011 marked the centenary of the publication of the SALJ by Juta: an exceptional anniversary. This is not a time to review the history of the relationship between Juta, the SALJ, and its various editors. This task has been carried out several times by Ellison Kahn in his inimitable style (see 'Fifty years of the Journal under Union' (1960) 77 SALJ 162; 'The birth and life of the South African Law Journal' (1983) 100 SALJ 594; 'Foreword' to Patricia Cobbledick and Mervyn Dendy The South African Law Journal Cumulative Index 1973-1997 (1997); 'Farewell! Fifty years' hard work comes to an end' (1999) 116 SALJ 691; 'Speech at the Juta Dinner at the South African Law Journal Jubilee Conference' (2004) 121 SALJ 271). But a short commemorative tribute seems apt to commemorate the liaison between the two parties.
- Full Text: false
- Date Issued: 2012
The end of the road for the Roman rule of risk in sale?
- Authors: Glover, Graham B
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70550 , vital:29674 , https://hdl.handle.net/10520/EJC127052
- Description: The venerable Roman rule of risk in the law of sale – “perfecta emptione periculum est emptoris” – has always been a rule that has courted controversy, be it in the South African legal system or others where it has operated. In an excellent piece of analytical historical scholarship titled “Perfecta emptione periculum est emptoris: Why all the fuss?” Van den Bergh argued in 2008 that, despite all the ink that has been spent on critiquing the rule in the thousands of years that have passed since its genesis, the rule has endured, and there are indeed reasons (partly practical and partly policy-related) that have justified its resilience. In this article I do not wish to dispute her carefully researched historiographical conclusions. Rather, I wish to suggest that circumstances may now have changed. The agent of this change is, not unexpectedly, the Consumer Protection Act 68 of 2008 (the act). The act, simply stated, changes the rule of risk that applies to consumer sale contracts. The way in which the legislation does so will be discussed fully in part 4 of the article below. But what does this legislative shift mean for the common-law rule, bearing in mind that not all contracts are contracts that fall under the act? In the remainder of the article I shall discuss whether the time has come for the common-law rule to take its bow, particularly in the light of the criticism it has always faced, the clear and consistent statements of policy that emerge from the act and comparative modern sources about where risk should fall, and the interests of fairness and uniformity of treatment of the parties to a sale contract.
- Full Text: false
- Date Issued: 2012
- Authors: Glover, Graham B
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70550 , vital:29674 , https://hdl.handle.net/10520/EJC127052
- Description: The venerable Roman rule of risk in the law of sale – “perfecta emptione periculum est emptoris” – has always been a rule that has courted controversy, be it in the South African legal system or others where it has operated. In an excellent piece of analytical historical scholarship titled “Perfecta emptione periculum est emptoris: Why all the fuss?” Van den Bergh argued in 2008 that, despite all the ink that has been spent on critiquing the rule in the thousands of years that have passed since its genesis, the rule has endured, and there are indeed reasons (partly practical and partly policy-related) that have justified its resilience. In this article I do not wish to dispute her carefully researched historiographical conclusions. Rather, I wish to suggest that circumstances may now have changed. The agent of this change is, not unexpectedly, the Consumer Protection Act 68 of 2008 (the act). The act, simply stated, changes the rule of risk that applies to consumer sale contracts. The way in which the legislation does so will be discussed fully in part 4 of the article below. But what does this legislative shift mean for the common-law rule, bearing in mind that not all contracts are contracts that fall under the act? In the remainder of the article I shall discuss whether the time has come for the common-law rule to take its bow, particularly in the light of the criticism it has always faced, the clear and consistent statements of policy that emerge from the act and comparative modern sources about where risk should fall, and the interests of fairness and uniformity of treatment of the parties to a sale contract.
- Full Text: false
- Date Issued: 2012
Molecular catalysis of the oxygen reduction reaction by iron porphyrin catalysts tethered into Nafion layers
- He, Qinggang, Mugadza, Tawanda, Kang, Xiongwu, Zhu, Xiaobing, Chen, Shaowei, Kerr, John, Nyokong, Tebello
- Authors: He, Qinggang , Mugadza, Tawanda , Kang, Xiongwu , Zhu, Xiaobing , Chen, Shaowei , Kerr, John , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243168 , vital:51123 , xlink:href="https://doi.org/10.1016/j.jpowsour.2012.05.043"
- Description: This study was motivated by the need for improved understanding of the kinetics and transport phenomena in a homogeneous catalyst system for the oxygen reduction reaction (ORR). Direct interaction between the sulfonic groups of Nafion and an Fe(III) meso-tetra(N-methyl-4-pyridyl) porphine chloride (Fe(III)TMPyP) compound was observed using FTIR and in situ UV–Vis spectroelectrochemical characterizations. A positive shift of the half wave potential value (E1/2) for ORR on the iron porphyrin catalyst (Fe(III)TMPyP) was observed upon addition of a specific quantity of Nafion ionomer on a glassy carbon working electrode, indicating not only a faster charge transfer rate but also the role of protonation in the oxygen reduction reaction (ORR) process. A membrane electrode assembly (MEA) was made as a sandwich of a Pt-coated anode, a Nafion® 212 membrane, and a Fe(III)TMPyP + Nafion ionomer-coated cathode. This three-dimensional catalysis system has been demonstrated to be working in a H2/O2 proton exchange membrane (PEM) fuel cell test.
- Full Text:
- Date Issued: 2012
- Authors: He, Qinggang , Mugadza, Tawanda , Kang, Xiongwu , Zhu, Xiaobing , Chen, Shaowei , Kerr, John , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243168 , vital:51123 , xlink:href="https://doi.org/10.1016/j.jpowsour.2012.05.043"
- Description: This study was motivated by the need for improved understanding of the kinetics and transport phenomena in a homogeneous catalyst system for the oxygen reduction reaction (ORR). Direct interaction between the sulfonic groups of Nafion and an Fe(III) meso-tetra(N-methyl-4-pyridyl) porphine chloride (Fe(III)TMPyP) compound was observed using FTIR and in situ UV–Vis spectroelectrochemical characterizations. A positive shift of the half wave potential value (E1/2) for ORR on the iron porphyrin catalyst (Fe(III)TMPyP) was observed upon addition of a specific quantity of Nafion ionomer on a glassy carbon working electrode, indicating not only a faster charge transfer rate but also the role of protonation in the oxygen reduction reaction (ORR) process. A membrane electrode assembly (MEA) was made as a sandwich of a Pt-coated anode, a Nafion® 212 membrane, and a Fe(III)TMPyP + Nafion ionomer-coated cathode. This three-dimensional catalysis system has been demonstrated to be working in a H2/O2 proton exchange membrane (PEM) fuel cell test.
- Full Text:
- Date Issued: 2012
Quality of life in Grahamstown, East London and Mdantsane: preliminary result
- Helliker, Kirk D, Bekker, Simon, Lambie, Eileen
- Authors: Helliker, Kirk D , Bekker, Simon , Lambie, Eileen
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144756 , vital:38376 , DOI: 10.1080/02580144.1981.10428933
- Description: A quality of life survey amongst residents of three Eastern Cape towns, viz. Grahamstown, East London, and Mdantsane, shows that the attitudes to home and neighbourhood which urban residents in the Eastern Cape develop, are fashioned in large part by both the residential “group area” in which these urban dwellers live, and by their socio-economic status. White residents, overwhelmingly, are satisfied with their diets, their municipality, their homes. They feel safe in their homes and are satisfied that police protection is available if needed. For black residents fear of poverty and unemployment, of physical violence, and dissatisfaction with an inadequate diet is widespread. Indian and coloured urban residents who are generally perceived as minorities in Grahamstown and East London, occupy an intermediate position. Their residential areas are sited close to predominantly low income black residential areas. Higher income Indian and coloured households show lower rates of dissatisfaction with diet, housing, and municipal services than the black community.
- Full Text:
- Date Issued: 2012
- Authors: Helliker, Kirk D , Bekker, Simon , Lambie, Eileen
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144756 , vital:38376 , DOI: 10.1080/02580144.1981.10428933
- Description: A quality of life survey amongst residents of three Eastern Cape towns, viz. Grahamstown, East London, and Mdantsane, shows that the attitudes to home and neighbourhood which urban residents in the Eastern Cape develop, are fashioned in large part by both the residential “group area” in which these urban dwellers live, and by their socio-economic status. White residents, overwhelmingly, are satisfied with their diets, their municipality, their homes. They feel safe in their homes and are satisfied that police protection is available if needed. For black residents fear of poverty and unemployment, of physical violence, and dissatisfaction with an inadequate diet is widespread. Indian and coloured urban residents who are generally perceived as minorities in Grahamstown and East London, occupy an intermediate position. Their residential areas are sited close to predominantly low income black residential areas. Higher income Indian and coloured households show lower rates of dissatisfaction with diet, housing, and municipal services than the black community.
- Full Text:
- Date Issued: 2012
Marx, Weber and NGOs:
- Authors: Helliker, Kirk D
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144738 , vital:38375 , DOI: 10.1080/21528586.2007.10419171
- Description: This article offers a sociological understanding of intermediary NGOs in the modern world. In does so by drawing on certain epistemological insights of Marx and Weber, and this entails methodologies of both deconstruction and reconstruction. In arguing against a sociological behaviourism that pervades the NGO literature, the article conceptualises intermediary NGOs as a ‘social form’ embodying contradictory relations. For analytical purposes, the contradiction between ‘the global’ and ‘the local’ is brought to the fore.
- Full Text:
- Date Issued: 2012
- Authors: Helliker, Kirk D
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144738 , vital:38375 , DOI: 10.1080/21528586.2007.10419171
- Description: This article offers a sociological understanding of intermediary NGOs in the modern world. In does so by drawing on certain epistemological insights of Marx and Weber, and this entails methodologies of both deconstruction and reconstruction. In arguing against a sociological behaviourism that pervades the NGO literature, the article conceptualises intermediary NGOs as a ‘social form’ embodying contradictory relations. For analytical purposes, the contradiction between ‘the global’ and ‘the local’ is brought to the fore.
- Full Text:
- Date Issued: 2012
Radical thinking in South Africa’s age of retreat
- Helliker, Kirk D, Vale, Peter C J
- Authors: Helliker, Kirk D , Vale, Peter C J
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71214 , vital:29818 , https://doi.org/10.1177/0021909612442654
- Description: This article traces the rise and fall of radical praxis in South Africa and offers a critique of the prevailing practices of former Marxists under post-apartheid conditions. Western Marxism emerged in the 1970s in South Africa and Marxist activists became deeply involved in the liberation movements. With the unravelling of apartheid, the main liberation forces made a social pact with capitalist forces and former Marxists embraced a statist project. In the context of the rise of ‘new’ social movements, radical thinking of a more Libertarian kind is emerging in contemporary South Africa.
- Full Text: false
- Date Issued: 2012
- Authors: Helliker, Kirk D , Vale, Peter C J
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71214 , vital:29818 , https://doi.org/10.1177/0021909612442654
- Description: This article traces the rise and fall of radical praxis in South Africa and offers a critique of the prevailing practices of former Marxists under post-apartheid conditions. Western Marxism emerged in the 1970s in South Africa and Marxist activists became deeply involved in the liberation movements. With the unravelling of apartheid, the main liberation forces made a social pact with capitalist forces and former Marxists embraced a statist project. In the context of the rise of ‘new’ social movements, radical thinking of a more Libertarian kind is emerging in contemporary South Africa.
- Full Text: false
- Date Issued: 2012
Civil society and state-centred struggles
- Authors: Helliker, Kirk D
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71231 , vital:29821 , https://doi.org/10.1080/02589001.2012.641723
- Description: This article is about civil society and state-centred struggles in contemporary Zimbabwe. I first identify and outline three current understandings of civil society. Two understandings (one Liberal, one Radical) are state-centric and exist firmly within the logic of state discourses and state politics. A third understanding, also Radical, is society-centric and speaks about politics existing at a distance from the state and possibly beyond the boundaries of civil society. This civil society-state discussion frames the second section of the article, which looks specifically at Zimbabwe. It details civil society as contested terrain (from the late 1990s onwards) within the context of a scholarly debate about agrarian transformation and political change. This debate, which reproduces (in theoretical garb) the key political society (or party) fault-lines within Zimbabwean society, has taken place primarily within the restricted confines of state-centred discourses.
- Full Text:
- Date Issued: 2012
- Authors: Helliker, Kirk D
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71231 , vital:29821 , https://doi.org/10.1080/02589001.2012.641723
- Description: This article is about civil society and state-centred struggles in contemporary Zimbabwe. I first identify and outline three current understandings of civil society. Two understandings (one Liberal, one Radical) are state-centric and exist firmly within the logic of state discourses and state politics. A third understanding, also Radical, is society-centric and speaks about politics existing at a distance from the state and possibly beyond the boundaries of civil society. This civil society-state discussion frames the second section of the article, which looks specifically at Zimbabwe. It details civil society as contested terrain (from the late 1990s onwards) within the context of a scholarly debate about agrarian transformation and political change. This debate, which reproduces (in theoretical garb) the key political society (or party) fault-lines within Zimbabwean society, has taken place primarily within the restricted confines of state-centred discourses.
- Full Text:
- Date Issued: 2012
Toxic effect of herbicides used for water hyacinth control on two insects released for its biological control in South Africa
- Authors: Hill, Martin P
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69960 , vital:29601 , https://doi.org/10.1080/09583157.2012.725825
- Description: The integrated control of water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae) has become necessary in South Africa, as biological control alone is perceived to be too slow in controlling the weed. In total, seven insect biological control agents have been released on water hyacinth in South Africa. At the same time, herbicides are applied by the water authorities in areas where the weed continues to be troublesome. This study investigated the assumption that the two control methods are compatible by testing the direct toxicity of a range of herbicide formulations and surfactants on two of the biological control agents released against water hyacinth, the weevil, Neochetina eichhorniae Warner (Coleoptera: Curculionidae) and the water hyacinth mirid,Eccritotarsus catarinensis (Carvalho) (Hemiptera: Miridae). A number of the formulations used resulted in significant mortality of the mirid and the weevil. Products containing 2,4-D amine and diquat as active ingredients caused higher mortality of both agents (up to 80% for the mirid) than formulations containing glyphosate. Furthermore, when surfactants were added to enhance herbicide efficiency, it resulted in increased toxicity to the insects. We recommend that glyphosate formulations should be used in integrated control programmes, and that surfactants be avoided in order to reduce the toxic nature of spray formulations to the insect biological control agents released against water hyacinth.
- Full Text:
- Date Issued: 2012
- Authors: Hill, Martin P
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69960 , vital:29601 , https://doi.org/10.1080/09583157.2012.725825
- Description: The integrated control of water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae) has become necessary in South Africa, as biological control alone is perceived to be too slow in controlling the weed. In total, seven insect biological control agents have been released on water hyacinth in South Africa. At the same time, herbicides are applied by the water authorities in areas where the weed continues to be troublesome. This study investigated the assumption that the two control methods are compatible by testing the direct toxicity of a range of herbicide formulations and surfactants on two of the biological control agents released against water hyacinth, the weevil, Neochetina eichhorniae Warner (Coleoptera: Curculionidae) and the water hyacinth mirid,Eccritotarsus catarinensis (Carvalho) (Hemiptera: Miridae). A number of the formulations used resulted in significant mortality of the mirid and the weevil. Products containing 2,4-D amine and diquat as active ingredients caused higher mortality of both agents (up to 80% for the mirid) than formulations containing glyphosate. Furthermore, when surfactants were added to enhance herbicide efficiency, it resulted in increased toxicity to the insects. We recommend that glyphosate formulations should be used in integrated control programmes, and that surfactants be avoided in order to reduce the toxic nature of spray formulations to the insect biological control agents released against water hyacinth.
- Full Text:
- Date Issued: 2012
A model for the analysis of small group interaction–and beyond?:
- Authors: Hunt, Sally
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/139171 , vital:37711 , DOI: 10.1080/10118063.1997.9724122
- Description: This article describes a branching model developed for the analysis of interaction in small teaching groups in a tertiary setting. Based within Conversation Analysis, the model constitutes a set of justifications for the validity of utterances in terms of their place on the conversational floor. Examples of the classifications included in the model are provided from a broader study of interaction in tutorials at an Eastern Cape university. It is suggested that while the model was developed for a specific context, it could be adapted for use in a variety of contexts.
- Full Text:
- Date Issued: 2012
- Authors: Hunt, Sally
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/139171 , vital:37711 , DOI: 10.1080/10118063.1997.9724122
- Description: This article describes a branching model developed for the analysis of interaction in small teaching groups in a tertiary setting. Based within Conversation Analysis, the model constitutes a set of justifications for the validity of utterances in terms of their place on the conversational floor. Examples of the classifications included in the model are provided from a broader study of interaction in tutorials at an Eastern Cape university. It is suggested that while the model was developed for a specific context, it could be adapted for use in a variety of contexts.
- Full Text:
- Date Issued: 2012
Study South Africa
- International Education Association of South Africa (IEASA), Jooste, Nico
- Authors: International Education Association of South Africa (IEASA) , Jooste, Nico
- Date: 2012
- Subjects: Education, Higher -- South Africa , Universities and colleges -- South Africa , Technical Institutes -- South Africa , Vocational guidance -- South Africa
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/64928 , vital:28637 , ISBN 9780620542661
- Description: [Extract from article by Ms Merle Hodges]: A recent article points to the feeling of alienation that students feel when studying away from home. It seeks to address the problem by establishing a range of fora where foreign students can feel more ‘at home’. It encourages host students to be more willing to accommodate these ‘outsiders’ in order to boost the reputation of the institution. Most of these initiatives are slightly patronising, but obviously well-meant. The overriding sense behind the article is that international students, within higher education institutions, are a benevolent burden. International students should be looked after, because universities are generally maternal (they are someone’s alma mater after all), places of kindness (they literally give away knowledge) and generally care for others (community outreach is fundamental to most universities). More importantly, international students – in places like the USA and UK – generate additional funding in an environment where government and federal funding is drying up. But what if four out of every ten students in the world who graduated were from China and India? In the next eight years? That genial inconvenience now becomes an imperative. These are the predictions by such august organisations as The British Council and the education branch of the OECD. It is also anticipated that these countries will not be in a position to educate this number of students internally. Which, in turn, suggests that there will be mass outflows at the undergraduate level and, by sheer dint of numbers, also means that internationalisation is heading towards a compounding acceleration in numbers. Where then does internationalisation stand? It will no longer be an altruistic add-on, but core business to the lifeblood of the universities across the globe. As far back as 1994, Jane Knight understood internationalisation as a phenomenon that would have a profound impact on the functions and structures of the university. “Internationalization,” she points out, “is the process of integrating an international, intercultural, global outlook into the major functions of a university – teaching, SRC, and service functions.” Over the past year arguments have been made that suggest that global shifts in student demographics are not the ‘province’ of South African higher education and that our obligation is to focus internally, on poverty alleviation and job creation. This argument misses the point. The free flow of academics and students – especially the large number of postgraduate students from other countries already at our institutions – are working with our academics on solving exactly these kinds of problems. IEASA is no longer only about the 60 000 students who migrate to our shores annually. It’s about what they learn and the diverse experiences that they will go through; experiences that will change them for life and will inevitably bring them to a different understanding of the world that we, collectively, are presently fashioning. , 12th Edition
- Full Text:
- Date Issued: 2012
- Authors: International Education Association of South Africa (IEASA) , Jooste, Nico
- Date: 2012
- Subjects: Education, Higher -- South Africa , Universities and colleges -- South Africa , Technical Institutes -- South Africa , Vocational guidance -- South Africa
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/64928 , vital:28637 , ISBN 9780620542661
- Description: [Extract from article by Ms Merle Hodges]: A recent article points to the feeling of alienation that students feel when studying away from home. It seeks to address the problem by establishing a range of fora where foreign students can feel more ‘at home’. It encourages host students to be more willing to accommodate these ‘outsiders’ in order to boost the reputation of the institution. Most of these initiatives are slightly patronising, but obviously well-meant. The overriding sense behind the article is that international students, within higher education institutions, are a benevolent burden. International students should be looked after, because universities are generally maternal (they are someone’s alma mater after all), places of kindness (they literally give away knowledge) and generally care for others (community outreach is fundamental to most universities). More importantly, international students – in places like the USA and UK – generate additional funding in an environment where government and federal funding is drying up. But what if four out of every ten students in the world who graduated were from China and India? In the next eight years? That genial inconvenience now becomes an imperative. These are the predictions by such august organisations as The British Council and the education branch of the OECD. It is also anticipated that these countries will not be in a position to educate this number of students internally. Which, in turn, suggests that there will be mass outflows at the undergraduate level and, by sheer dint of numbers, also means that internationalisation is heading towards a compounding acceleration in numbers. Where then does internationalisation stand? It will no longer be an altruistic add-on, but core business to the lifeblood of the universities across the globe. As far back as 1994, Jane Knight understood internationalisation as a phenomenon that would have a profound impact on the functions and structures of the university. “Internationalization,” she points out, “is the process of integrating an international, intercultural, global outlook into the major functions of a university – teaching, SRC, and service functions.” Over the past year arguments have been made that suggest that global shifts in student demographics are not the ‘province’ of South African higher education and that our obligation is to focus internally, on poverty alleviation and job creation. This argument misses the point. The free flow of academics and students – especially the large number of postgraduate students from other countries already at our institutions – are working with our academics on solving exactly these kinds of problems. IEASA is no longer only about the 60 000 students who migrate to our shores annually. It’s about what they learn and the diverse experiences that they will go through; experiences that will change them for life and will inevitably bring them to a different understanding of the world that we, collectively, are presently fashioning. , 12th Edition
- Full Text:
- Date Issued: 2012
Photophysics and photochemistry of octaglucosylated zinc phthalocyanine derivatives
- Iqbal, Zafar, Ogunsipe, Abimbola, Nyokong, Tebello, Lyubimtsev, Alexey, Hanack, Michael, Ziegler, Thomas
- Authors: Iqbal, Zafar , Ogunsipe, Abimbola , Nyokong, Tebello , Lyubimtsev, Alexey , Hanack, Michael , Ziegler, Thomas
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244416 , vital:51255 , xlink:href="https://doi.org/10.1142/S1088424612500630"
- Description: The ground state electronic absorption spectra, photophysics and photochemistry of amphiphilic octaglucosylated zinc phthalocyanines containing oxygen or sulfur bridges are presented. Triplet quantum yield values for the two dyes (in DMF and DMSO) vary between 0.71 and 0.84, while singlet quantum yield values lie between 0.63 and 0.75. Fluorescence lifetimes were determined experimentally by time correlated single photon counting and semi-empirically by fluorescence quenching techniques; and values from both methods were within the same range. Kinetic data were obtained for the quenching of the triplet state of the phthalocyanines by ground state molecular oxygen; the bimolecular collisional quenching rate constant range between 2.35 × 108 and 1.13 × 109 M-1.s-1. These values suggest that triplet states of the dyes are effectively quenched by ground molecular oxygen.
- Full Text:
- Date Issued: 2012
- Authors: Iqbal, Zafar , Ogunsipe, Abimbola , Nyokong, Tebello , Lyubimtsev, Alexey , Hanack, Michael , Ziegler, Thomas
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244416 , vital:51255 , xlink:href="https://doi.org/10.1142/S1088424612500630"
- Description: The ground state electronic absorption spectra, photophysics and photochemistry of amphiphilic octaglucosylated zinc phthalocyanines containing oxygen or sulfur bridges are presented. Triplet quantum yield values for the two dyes (in DMF and DMSO) vary between 0.71 and 0.84, while singlet quantum yield values lie between 0.63 and 0.75. Fluorescence lifetimes were determined experimentally by time correlated single photon counting and semi-empirically by fluorescence quenching techniques; and values from both methods were within the same range. Kinetic data were obtained for the quenching of the triplet state of the phthalocyanines by ground state molecular oxygen; the bimolecular collisional quenching rate constant range between 2.35 × 108 and 1.13 × 109 M-1.s-1. These values suggest that triplet states of the dyes are effectively quenched by ground molecular oxygen.
- Full Text:
- Date Issued: 2012
Spectral, photophysical and photochemical properties of tetra-and octaglycosylated zinc phthalocyanines
- Iqbal, Zafar, Masilela, Nkosiphile, Nyokong, Tebello, Lyubimtsev, Alexey, Hanack, Michael, Ziegler, Thomas
- Authors: Iqbal, Zafar , Masilela, Nkosiphile , Nyokong, Tebello , Lyubimtsev, Alexey , Hanack, Michael , Ziegler, Thomas
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244428 , vital:51256 , xlink:href="https://doi.org/10.1039/c2pp05348a"
- Description: Photophysical and photochemical properties of a series of tetra- and octaglycosylated zinc phthalocyanines (ZnPcs) substituted with glucose and galactose moieties have been reported. Spectral properties of these phthalocyanines are compared in DMSO. Absorption spectra of the non-peripherally tetra-substituted ZnPcs 2 showed a significant red shift in their Q-band maxima as compared to the peripherally substituted analog 1. All the complexes gave high triplet quantum yields ranging from 0.68 to 0.88, whereas triplet lifetimes were in the range of 100–430 µs in argon-saturated solutions. The octagalactosylated ZnPc 3b showed the highest triplet quantum yield and singlet oxygen quantum yield of 0.88 and 0.69, respectively. The fluorescence quantum yields and lifetimes of all the compounds under investigation were within the range of zinc phthalocyanine complexes.
- Full Text:
- Date Issued: 2012
- Authors: Iqbal, Zafar , Masilela, Nkosiphile , Nyokong, Tebello , Lyubimtsev, Alexey , Hanack, Michael , Ziegler, Thomas
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244428 , vital:51256 , xlink:href="https://doi.org/10.1039/c2pp05348a"
- Description: Photophysical and photochemical properties of a series of tetra- and octaglycosylated zinc phthalocyanines (ZnPcs) substituted with glucose and galactose moieties have been reported. Spectral properties of these phthalocyanines are compared in DMSO. Absorption spectra of the non-peripherally tetra-substituted ZnPcs 2 showed a significant red shift in their Q-band maxima as compared to the peripherally substituted analog 1. All the complexes gave high triplet quantum yields ranging from 0.68 to 0.88, whereas triplet lifetimes were in the range of 100–430 µs in argon-saturated solutions. The octagalactosylated ZnPc 3b showed the highest triplet quantum yield and singlet oxygen quantum yield of 0.88 and 0.69, respectively. The fluorescence quantum yields and lifetimes of all the compounds under investigation were within the range of zinc phthalocyanine complexes.
- Full Text:
- Date Issued: 2012