Academic literacy in management education
- Pearse, Noel J, Amos, Trevor L
- Authors: Pearse, Noel J , Amos, Trevor L
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/270065 , vital:54392 , xlink:href="https://hdl.handle.net/10520/EJC36783"
- Description: Although management education aims to equip students with relevant knowledge, skills and competencies, making explicit and developing the cognitive thought processes necessary for management students to deal effectively with the current and future demands of the world of work, have been neglected. This article argues for the development of "complicated understanding" (Bartunek, Gordon and Weathersby 1983) in management students, through cultivating academic literacy. Using mediation, reflective inquiry and reflective writing interactively, it is illustrated how academic literacy could be promoted at the post-graduate level.
- Full Text:
- Date Issued: 2000
- Authors: Pearse, Noel J , Amos, Trevor L
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/270065 , vital:54392 , xlink:href="https://hdl.handle.net/10520/EJC36783"
- Description: Although management education aims to equip students with relevant knowledge, skills and competencies, making explicit and developing the cognitive thought processes necessary for management students to deal effectively with the current and future demands of the world of work, have been neglected. This article argues for the development of "complicated understanding" (Bartunek, Gordon and Weathersby 1983) in management students, through cultivating academic literacy. Using mediation, reflective inquiry and reflective writing interactively, it is illustrated how academic literacy could be promoted at the post-graduate level.
- Full Text:
- Date Issued: 2000
An investigation into the neuroprotective properties of ibuprofen
- Lambat, Zaynab Y, Conrad, Natasha, Anoopkumar-Dukie, Shailendra, Walker, Roderick B, Daya, Santylal
- Authors: Lambat, Zaynab Y , Conrad, Natasha , Anoopkumar-Dukie, Shailendra , Walker, Roderick B , Daya, Santylal
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184335 , vital:44209 , xlink:href="https://doi.org/10.1023/A:1011115006856"
- Description: There is increasing evidence suggesting a protective role for anti-inflammatory medications in neurological disorders such as Alzheimer's disease (AD). While there has not been any direct evidence for this, a number of clinical studies indicate that those patients who have had a history of nonsteroidal anti-inflammatory use, have a lower incidence of AD. Since there is currently no evidence on the mechanism by which these agents offer possible neuroprotection, we investigated the potential neuroprotective properties of the nonsteroidal anti-inflammatory drug, ibuprofen, by examining whether this agent could reduce lipid peroxidation and superoxide radical generation. Quinolinic acid and cyanide, known neurotoxins, were used to induce lipid peroxidation and superoxide anion formation respectively, in rat brain homogenate. The results show that ibuprofen significantly (p more than 0.05) reduced quinolinic acid-induced lipid peroxidation and cyanide-induced superoxide production. The results of the present report therefore suggest a possible mechanism for the neuroprotective effect of ibuprofen.
- Full Text: false
- Date Issued: 2000
- Authors: Lambat, Zaynab Y , Conrad, Natasha , Anoopkumar-Dukie, Shailendra , Walker, Roderick B , Daya, Santylal
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184335 , vital:44209 , xlink:href="https://doi.org/10.1023/A:1011115006856"
- Description: There is increasing evidence suggesting a protective role for anti-inflammatory medications in neurological disorders such as Alzheimer's disease (AD). While there has not been any direct evidence for this, a number of clinical studies indicate that those patients who have had a history of nonsteroidal anti-inflammatory use, have a lower incidence of AD. Since there is currently no evidence on the mechanism by which these agents offer possible neuroprotection, we investigated the potential neuroprotective properties of the nonsteroidal anti-inflammatory drug, ibuprofen, by examining whether this agent could reduce lipid peroxidation and superoxide radical generation. Quinolinic acid and cyanide, known neurotoxins, were used to induce lipid peroxidation and superoxide anion formation respectively, in rat brain homogenate. The results show that ibuprofen significantly (p more than 0.05) reduced quinolinic acid-induced lipid peroxidation and cyanide-induced superoxide production. The results of the present report therefore suggest a possible mechanism for the neuroprotective effect of ibuprofen.
- Full Text: false
- Date Issued: 2000
Brothers go solo on piano
- Authors: Thomas, Cornelius
- Date: 2000
- Subjects: Schilder, Tony Schilder, Ebrahim Kalil Jazz musicians
- Type: article
- Identifier: http://hdl.handle.net/10962/32775 , vital:24079 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017. , MS 20 018
- Description: Photocopied article from the newspaper The Daily Dispatch about two brothers who are Jazz musicians
- Full Text:
- Date Issued: 2000
- Authors: Thomas, Cornelius
- Date: 2000
- Subjects: Schilder, Tony Schilder, Ebrahim Kalil Jazz musicians
- Type: article
- Identifier: http://hdl.handle.net/10962/32775 , vital:24079 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017. , MS 20 018
- Description: Photocopied article from the newspaper The Daily Dispatch about two brothers who are Jazz musicians
- Full Text:
- Date Issued: 2000
Cape Town to host North Sea Jazz Festival
- Authors: Thomas, Cornelius
- Date: 2000
- Subjects: North Sea Jazz Festival -- South Africa -- Cape Town Performing arts -- South Africa Jazz musicians -- South Africa , North Sea Jazz Festival -- Marketing
- Type: article
- Identifier: http://hdl.handle.net/10962/33011 , vital:24104 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017. , MS 20 023
- Description: Photocopied article from the newspaper The Daily Dispatch about the North Sea Jazz Festival hosted by Cape Town
- Full Text:
- Date Issued: 2000
- Authors: Thomas, Cornelius
- Date: 2000
- Subjects: North Sea Jazz Festival -- South Africa -- Cape Town Performing arts -- South Africa Jazz musicians -- South Africa , North Sea Jazz Festival -- Marketing
- Type: article
- Identifier: http://hdl.handle.net/10962/33011 , vital:24104 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017. , MS 20 023
- Description: Photocopied article from the newspaper The Daily Dispatch about the North Sea Jazz Festival hosted by Cape Town
- Full Text:
- Date Issued: 2000
Comparative Spectroscopic and Electrochemical Properties of Bis (octakis (dodecylthio) naphthalocyaninato) europium (III) and Bis (tetra-tert-butylnaphthalocyaninato) europium (III) Complexes
- Nyokong, Tebello, Furuya, Fumio, Kobayashi, Nagao, Du, Daming, Liu, Wei, Jiang, Jianzhuang
- Authors: Nyokong, Tebello , Furuya, Fumio , Kobayashi, Nagao , Du, Daming , Liu, Wei , Jiang, Jianzhuang
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293174 , vital:57062 , xlink:href="https://doi.org/10.1021/ic990483b"
- Description: Bis(substituted-2,3-naphthalocyaninato)europium(III) complexes: bis(octakis(dodecylthio)-2,3-naphthalocyaninato)europium(III) {Eu[2,3-Nc(SC12H25)8]2, 1} and bis(tetra-tert-butyl-2,3-naphthalocyaninato)europium(III) {Eu[2,3-Nc(t-Bu)4]2, 2} have been synthesized by cyclic tetramerization of naphthalonitriles with Eu(acac)3·H2O in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in refluxing n-octanol. These compounds were characterized by UV−visible, magnetic circular dichroism (MCD), near-IR, IR, EPR, and mass spectroscopies. The absorption and MCD spectra of 1 showed splitting of the Q band, with peaks at 700 and 784 nm, red shifted from the Q band of 2 at 763 nm. The absorption and MCD spectral band deconvolution calculations of complex 1 gave two A terms in the Q-band region. The A terms are assigned to 2A2 → 2E1 transitions. Cyclic voltammograms of 1 and 2 showed reversible oxidation couples at E1/2 = −0.28 V (for 2) and −0.25 V (for 1) vs ferrocenium/ferrocene (Fc+/Fc). The second oxidation exhibited a complicated behavior for both complexes. The reduction couples for 2 were observed at E1/2 = −0.61, −1.64, −1.97, and −2.42 V, and for 1 they were observed at E1/2 = −0.62, −1.60, −1.86, and −2.27 V vs Fc+/Fc. Spectral changes observed on chemical oxidation and reduction of the complexes are presented, and the behaviors of 1 and 2 are compared.
- Full Text:
- Date Issued: 2000
- Authors: Nyokong, Tebello , Furuya, Fumio , Kobayashi, Nagao , Du, Daming , Liu, Wei , Jiang, Jianzhuang
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293174 , vital:57062 , xlink:href="https://doi.org/10.1021/ic990483b"
- Description: Bis(substituted-2,3-naphthalocyaninato)europium(III) complexes: bis(octakis(dodecylthio)-2,3-naphthalocyaninato)europium(III) {Eu[2,3-Nc(SC12H25)8]2, 1} and bis(tetra-tert-butyl-2,3-naphthalocyaninato)europium(III) {Eu[2,3-Nc(t-Bu)4]2, 2} have been synthesized by cyclic tetramerization of naphthalonitriles with Eu(acac)3·H2O in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in refluxing n-octanol. These compounds were characterized by UV−visible, magnetic circular dichroism (MCD), near-IR, IR, EPR, and mass spectroscopies. The absorption and MCD spectra of 1 showed splitting of the Q band, with peaks at 700 and 784 nm, red shifted from the Q band of 2 at 763 nm. The absorption and MCD spectral band deconvolution calculations of complex 1 gave two A terms in the Q-band region. The A terms are assigned to 2A2 → 2E1 transitions. Cyclic voltammograms of 1 and 2 showed reversible oxidation couples at E1/2 = −0.28 V (for 2) and −0.25 V (for 1) vs ferrocenium/ferrocene (Fc+/Fc). The second oxidation exhibited a complicated behavior for both complexes. The reduction couples for 2 were observed at E1/2 = −0.61, −1.64, −1.97, and −2.42 V, and for 1 they were observed at E1/2 = −0.62, −1.60, −1.86, and −2.27 V vs Fc+/Fc. Spectral changes observed on chemical oxidation and reduction of the complexes are presented, and the behaviors of 1 and 2 are compared.
- Full Text:
- Date Issued: 2000
Comparison of plant diversity in protected and communal lands in the Bushbuckridge lowveld savanna, South Africa
- Authors: Shackleton, Charlie M
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181885 , vital:43777 , xlink:href="https://doi.org/10.1016/S0006-3207(00)00001-X"
- Description: Patterns of higher plant species richness and beta diversity were assessed using standard Modified-Whittaker plots in relation to land use, slope position and mean annual rainfall across a rainfall gradient in the savanna areas of the Bushbuckridge lowveld, South Africa. In particular, comparison of communal areas with adjacent protected areas was important in showing the impacts of potential changes in land use within an overarching catchment management plan. Although most of the protected areas considered preservation of biodiversity as their primary goal, they were characterised by significantly fewer plant species than the adjacent, highly utilised, communal lands, at both the plot and point scale. Slope position also had a significant effect on plant species richness, with eutrophic bottomlands having c. 30% more species than the dystrophic toplands. This adds weight to the need for greater public awareness for the judicious use and management of the sensitive bottomlands, which fringe the primary drainage lines that are vital for sustained supplies of good quality surface water in this semi-arid environment. The total number of species increased with increasing mean annual rainfall across the rainfall gradient. This suggests that, if the catchment management plan aims to identify additional areas for conservation, the higher rainfall areas should be the first to be assessed. Species turnover was greater along the rainfall gradient than the catenal gradient between toplands and bottomlands.
- Full Text:
- Date Issued: 2000
- Authors: Shackleton, Charlie M
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181885 , vital:43777 , xlink:href="https://doi.org/10.1016/S0006-3207(00)00001-X"
- Description: Patterns of higher plant species richness and beta diversity were assessed using standard Modified-Whittaker plots in relation to land use, slope position and mean annual rainfall across a rainfall gradient in the savanna areas of the Bushbuckridge lowveld, South Africa. In particular, comparison of communal areas with adjacent protected areas was important in showing the impacts of potential changes in land use within an overarching catchment management plan. Although most of the protected areas considered preservation of biodiversity as their primary goal, they were characterised by significantly fewer plant species than the adjacent, highly utilised, communal lands, at both the plot and point scale. Slope position also had a significant effect on plant species richness, with eutrophic bottomlands having c. 30% more species than the dystrophic toplands. This adds weight to the need for greater public awareness for the judicious use and management of the sensitive bottomlands, which fringe the primary drainage lines that are vital for sustained supplies of good quality surface water in this semi-arid environment. The total number of species increased with increasing mean annual rainfall across the rainfall gradient. This suggests that, if the catchment management plan aims to identify additional areas for conservation, the higher rainfall areas should be the first to be assessed. Species turnover was greater along the rainfall gradient than the catenal gradient between toplands and bottomlands.
- Full Text:
- Date Issued: 2000
Cyanide-induced free radical production and lipid peroxidation in rat brain homogenate is reduced by aspirin
- Daya, Santylal, Walker, Roderick B, Anoopkumar-Dukie, Shailendra
- Authors: Daya, Santylal , Walker, Roderick B , Anoopkumar-Dukie, Shailendra
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184346 , vital:44210 , xlink:href="https://doi.org/10.1007/BF02674529"
- Description: The neuroprotective properties of aspirin were investigated using cyanide-induced neurotoxicity as model. Cyanide, a known neurotoxic agent significantly increased lipid peroxidation and superoxide anion levels in rat brain homogenate in a concentration-dependent manner (0.25–1.0 mM). When homogenate, containing 1.0 mM KCN was cotreated with aspirin (1.0 mM) there was a significant decrease in lipid peroxidation. Aspirin (0.5 mM and 1.0 mM) also significantly reduced KCN-induced superoxide anion generation. The results of the present report therefore indicate a neuroprotective role for aspirin.
- Full Text:
- Date Issued: 2000
- Authors: Daya, Santylal , Walker, Roderick B , Anoopkumar-Dukie, Shailendra
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184346 , vital:44210 , xlink:href="https://doi.org/10.1007/BF02674529"
- Description: The neuroprotective properties of aspirin were investigated using cyanide-induced neurotoxicity as model. Cyanide, a known neurotoxic agent significantly increased lipid peroxidation and superoxide anion levels in rat brain homogenate in a concentration-dependent manner (0.25–1.0 mM). When homogenate, containing 1.0 mM KCN was cotreated with aspirin (1.0 mM) there was a significant decrease in lipid peroxidation. Aspirin (0.5 mM and 1.0 mM) also significantly reduced KCN-induced superoxide anion generation. The results of the present report therefore indicate a neuroprotective role for aspirin.
- Full Text:
- Date Issued: 2000
Dee Dee goes the distance
- Authors: Thomas, Cornelius
- Date: 2000
- Subjects: Bridgewater, Dee Dee Jazz musicians -- United States -- Biography
- Type: article
- Identifier: http://hdl.handle.net/10962/32968 , vital:24099 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017. , MS 20 022
- Description: Photocopied article from the newspaper The Daily Dispatch about Jazz musicians
- Full Text:
- Date Issued: 2000
- Authors: Thomas, Cornelius
- Date: 2000
- Subjects: Bridgewater, Dee Dee Jazz musicians -- United States -- Biography
- Type: article
- Identifier: http://hdl.handle.net/10962/32968 , vital:24099 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017. , MS 20 022
- Description: Photocopied article from the newspaper The Daily Dispatch about Jazz musicians
- Full Text:
- Date Issued: 2000
Direct use values of secondary resources harvested from communal savannas in the Bushbuckridge lowveld, South Africa
- Shackleton, Charlie M, Shackleton, Sheona E
- Authors: Shackleton, Charlie M , Shackleton, Sheona E
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182798 , vital:43875 , xlink:href="https://www.cabdirect.org/cabdirect/abstract/20000614194"
- Description: This study reports on the direct use value of secondary resources harvested by rural communities in a savanna region of South Africa. Data pertaining to the use, amount and direct use value of 11 secondary resources were presented individually, along with a final composite value. Only five resources (fuelwood, construction wood, edible fruits, edible herbs, and medicinal plants), individually accounted for more than 10% of the total value per hectare (US$ 141), and together they represented over 94% of the total value per hectare. On a per household basis, only 3 of the 11 resources contributed 10% or more to the total direct use value (US$ 386 used at home and US$ 767 traded), and together contributed greater than 71% of the total direct use value per household. Two-thirds of the value per household was traded locally with other households or regionally, rather than consumed at home. The total value per hectare compared favourably with other land uses within the region, except for capital intensive enterprises. The returns to collecting and selling secondary resources were higher than those paid for local agricultural wage labour. The extraction rates of several of the secondary resources are probably sustainable but not for the more important ones such as fuelwood, construction wood and medicinal plants.
- Full Text:
- Date Issued: 2000
- Authors: Shackleton, Charlie M , Shackleton, Sheona E
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182798 , vital:43875 , xlink:href="https://www.cabdirect.org/cabdirect/abstract/20000614194"
- Description: This study reports on the direct use value of secondary resources harvested by rural communities in a savanna region of South Africa. Data pertaining to the use, amount and direct use value of 11 secondary resources were presented individually, along with a final composite value. Only five resources (fuelwood, construction wood, edible fruits, edible herbs, and medicinal plants), individually accounted for more than 10% of the total value per hectare (US$ 141), and together they represented over 94% of the total value per hectare. On a per household basis, only 3 of the 11 resources contributed 10% or more to the total direct use value (US$ 386 used at home and US$ 767 traded), and together contributed greater than 71% of the total direct use value per household. Two-thirds of the value per household was traded locally with other households or regionally, rather than consumed at home. The total value per hectare compared favourably with other land uses within the region, except for capital intensive enterprises. The returns to collecting and selling secondary resources were higher than those paid for local agricultural wage labour. The extraction rates of several of the secondary resources are probably sustainable but not for the more important ones such as fuelwood, construction wood and medicinal plants.
- Full Text:
- Date Issued: 2000
Electrocatalytic behavior of substituted cobalt phthalocyanines towards the oxidation of cysteine
- Maree, Suzanne, Nyokong, Tebello
- Authors: Maree, Suzanne , Nyokong, Tebello
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293268 , vital:57070 , xlink:href="https://doi.org/10.1016/S0022-0728(00)00281-3"
- Description: Ring substituted cobalt phthalocyanine complexes of the form CoPc(X)4, (where X=NH2, NO2, C(CH3)3, SO3H and COOH) are compared for their catalytic activities towards the oxidation of cysteine. The potential for the electrocatalytic oxidation of cysteine is closely related to the CoIII/CoII couple of the CoPc(X)4 complexes in acidic media and to the CoII/CoI couple in basic media. The catalytic currents and the oxidation potential for cysteine are dependent on the pH of the solution, the potential becoming less positive as the pH increases and the catalytic currents decreasing with increase in pH, for the same concentration of cysteine. The magnitudes of the catalytic currents (after ten scans) for cysteine oxidation at pH 8.3 and on electrodes modified with the CoPc(X)4 complexes increased with the nature of the ring substituent as follows: NO2 less than NH2 less than SO3H less than C(CH3)3 less than COOH.
- Full Text:
- Date Issued: 2000
- Authors: Maree, Suzanne , Nyokong, Tebello
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293268 , vital:57070 , xlink:href="https://doi.org/10.1016/S0022-0728(00)00281-3"
- Description: Ring substituted cobalt phthalocyanine complexes of the form CoPc(X)4, (where X=NH2, NO2, C(CH3)3, SO3H and COOH) are compared for their catalytic activities towards the oxidation of cysteine. The potential for the electrocatalytic oxidation of cysteine is closely related to the CoIII/CoII couple of the CoPc(X)4 complexes in acidic media and to the CoII/CoI couple in basic media. The catalytic currents and the oxidation potential for cysteine are dependent on the pH of the solution, the potential becoming less positive as the pH increases and the catalytic currents decreasing with increase in pH, for the same concentration of cysteine. The magnitudes of the catalytic currents (after ten scans) for cysteine oxidation at pH 8.3 and on electrodes modified with the CoPc(X)4 complexes increased with the nature of the ring substituent as follows: NO2 less than NH2 less than SO3H less than C(CH3)3 less than COOH.
- Full Text:
- Date Issued: 2000
Electrocatalytic behavior of substituted cobalt phthalocyanines towards the oxidation of cysteine
- Maree, Suzanne, Nyokong, Tebello
- Authors: Maree, Suzanne , Nyokong, Tebello
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293185 , vital:57063 , xlink:href="https://doi.org/10.1016/S0022-0728(00)00281-3"
- Description: Ring substituted cobalt phthalocyanine complexes of the form CoPc(X)4, (where X=NH2, NO2, C(CH3)3, SO3H and COOH) are compared for their catalytic activities towards the oxidation of cysteine. The potential for the electrocatalytic oxidation of cysteine is closely related to the CoIII/CoII couple of the CoPc(X)4 complexes in acidic media and to the CoII/CoI couple in basic media. The catalytic currents and the oxidation potential for cysteine are dependent on the pH of the solution, the potential becoming less positive as the pH increases and the catalytic currents decreasing with increase in pH, for the same concentration of cysteine. The magnitudes of the catalytic currents (after ten scans) for cysteine oxidation at pH 8.3 and on electrodes modified with the CoPc(X)4 complexes increased with the nature of the ring substituent as follows: NO2 less than NH2 less than SO3H less than C(CH3)3 less than COOH.
- Full Text:
- Date Issued: 2000
- Authors: Maree, Suzanne , Nyokong, Tebello
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293185 , vital:57063 , xlink:href="https://doi.org/10.1016/S0022-0728(00)00281-3"
- Description: Ring substituted cobalt phthalocyanine complexes of the form CoPc(X)4, (where X=NH2, NO2, C(CH3)3, SO3H and COOH) are compared for their catalytic activities towards the oxidation of cysteine. The potential for the electrocatalytic oxidation of cysteine is closely related to the CoIII/CoII couple of the CoPc(X)4 complexes in acidic media and to the CoII/CoI couple in basic media. The catalytic currents and the oxidation potential for cysteine are dependent on the pH of the solution, the potential becoming less positive as the pH increases and the catalytic currents decreasing with increase in pH, for the same concentration of cysteine. The magnitudes of the catalytic currents (after ten scans) for cysteine oxidation at pH 8.3 and on electrodes modified with the CoPc(X)4 complexes increased with the nature of the ring substituent as follows: NO2 less than NH2 less than SO3H less than C(CH3)3 less than COOH.
- Full Text:
- Date Issued: 2000
Electrocatalytic properties of vitamin B12 towards oxidation and reduction of nitric oxide
- Vilakazi, Sibulelo Lea, Nyokong, Tebello
- Authors: Vilakazi, Sibulelo Lea , Nyokong, Tebello
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293196 , vital:57064 , xlink:href="https://doi.org/10.1016/S0013-4686(00)00628-9"
- Description: This paper reports on the catalytic behaviour of cyanocobalamin (VB12) towards the reduction and oxidation of nitric oxide. When VB12 is adsorbed on glassy carbon electrodes, it catalyses the reduction of nitric oxide (NO) in pH 4 and 9 buffers. In the absence of NO, cyclic voltammetry shows that VB12 is reduced by a one-step two-electron reduction from CoIII to the CoI species. Addition of NO at pH 9 to solutions of VB12 resulted in the splitting of the cyclic voltammetry peaks as a result of a consecutive one-electron reduction of the central CoIII metal in VB12 to CoII and finally to CoI. The catalytic peak for oxidation of NO on a glassy carbon electrode modified with VB12 was observed at 1.21 V versus Ag∣AgCl, at pH 9. The products of the catalytic reduction of nitric oxide include ammonia and hydroxylamine.
- Full Text:
- Date Issued: 2000
- Authors: Vilakazi, Sibulelo Lea , Nyokong, Tebello
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293196 , vital:57064 , xlink:href="https://doi.org/10.1016/S0013-4686(00)00628-9"
- Description: This paper reports on the catalytic behaviour of cyanocobalamin (VB12) towards the reduction and oxidation of nitric oxide. When VB12 is adsorbed on glassy carbon electrodes, it catalyses the reduction of nitric oxide (NO) in pH 4 and 9 buffers. In the absence of NO, cyclic voltammetry shows that VB12 is reduced by a one-step two-electron reduction from CoIII to the CoI species. Addition of NO at pH 9 to solutions of VB12 resulted in the splitting of the cyclic voltammetry peaks as a result of a consecutive one-electron reduction of the central CoIII metal in VB12 to CoII and finally to CoI. The catalytic peak for oxidation of NO on a glassy carbon electrode modified with VB12 was observed at 1.21 V versus Ag∣AgCl, at pH 9. The products of the catalytic reduction of nitric oxide include ammonia and hydroxylamine.
- Full Text:
- Date Issued: 2000
Impact of fire frequency on woody community structure and soil nutrients in the Kruger National Park
- Shackleton, Charlie M, Scholes, Robert J
- Authors: Shackleton, Charlie M , Scholes, Robert J
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181874 , vital:43776 , xlink:href="https://doi.org/10.4102/koedoe.v43i1.210"
- Description: Although fire is recognised as an important determinant of the structure and function of South African savannas, there are few studies of long-term impacts. Controlled burning blocks of contrasting fire season and frequency have been maintained throughout the Kruger National Park for almost 50 years. This paper reports on a quantitative study of the Satara plots to determine the long-term impacts of fire frequency on woody community structure and soil nutrients. Increasing fire frequency significantly decreased woody plant basal area, biomass, density, height, and mean stem circumference. The number of stems per plant and the proportion of regenerative stems increased with increasing fire frequency. Effects on species richness of woody plants were inconsistent. There were no significant differences attributable to fire frequency for any of the soil variables except organic matter and magnesium. Organic carbon was highest in the fire exclusion treatment and lowest in soils from plots burnt triennially. Magnesium levels were greatest in the annually burnt soils and least in the triennial plots.
- Full Text:
- Date Issued: 2000
Impact of fire frequency on woody community structure and soil nutrients in the Kruger National Park
- Authors: Shackleton, Charlie M , Scholes, Robert J
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181874 , vital:43776 , xlink:href="https://doi.org/10.4102/koedoe.v43i1.210"
- Description: Although fire is recognised as an important determinant of the structure and function of South African savannas, there are few studies of long-term impacts. Controlled burning blocks of contrasting fire season and frequency have been maintained throughout the Kruger National Park for almost 50 years. This paper reports on a quantitative study of the Satara plots to determine the long-term impacts of fire frequency on woody community structure and soil nutrients. Increasing fire frequency significantly decreased woody plant basal area, biomass, density, height, and mean stem circumference. The number of stems per plant and the proportion of regenerative stems increased with increasing fire frequency. Effects on species richness of woody plants were inconsistent. There were no significant differences attributable to fire frequency for any of the soil variables except organic matter and magnesium. Organic carbon was highest in the fire exclusion treatment and lowest in soils from plots burnt triennially. Magnesium levels were greatest in the annually burnt soils and least in the triennial plots.
- Full Text:
- Date Issued: 2000
Incorporating the spatial component of fisheries data into stock assessment models
- Authors: Booth, Anthony J
- Date: 2000
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124800 , vital:35698 , https://doi.10.1006/jmsc.2000.0816
- Description: Fisheries-dependent and independent data have a strong spatial component. These data are also multi-dimensional, making them difficult to visualize and analyze, prompting the use of spatial analysis to facilitate an understanding of their relationships. One aspect of fisheries data that is often ignored is the distribution and abundance of a particular resource and the fishing patterns of its harvesting fisheries. In order to improve management advice, stock assessors need to incorporate the spatial component of these data into an existing assessment framework. This paper presents a three-dimensional visualization of the age-structure and fishery dependent and independent data associated with the sparid fish Pterogymnus laniarius on the Agulhas Bank, South Africa. A spatially-referenced spawner biomass per-recruit model is developed to illustrate the applicability of incorporating spatially referenced information in providing management advice. The model provided evidence that, even on a spatial scale, fishing mortality is significantly correlated to fishing effort. Areas of high levels of spawner biomass are noted, all of which corresponded to those geographic areas with a combination of low fishing effort and high adult biomass.
- Full Text:
- Date Issued: 2000
- Authors: Booth, Anthony J
- Date: 2000
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124800 , vital:35698 , https://doi.10.1006/jmsc.2000.0816
- Description: Fisheries-dependent and independent data have a strong spatial component. These data are also multi-dimensional, making them difficult to visualize and analyze, prompting the use of spatial analysis to facilitate an understanding of their relationships. One aspect of fisheries data that is often ignored is the distribution and abundance of a particular resource and the fishing patterns of its harvesting fisheries. In order to improve management advice, stock assessors need to incorporate the spatial component of these data into an existing assessment framework. This paper presents a three-dimensional visualization of the age-structure and fishery dependent and independent data associated with the sparid fish Pterogymnus laniarius on the Agulhas Bank, South Africa. A spatially-referenced spawner biomass per-recruit model is developed to illustrate the applicability of incorporating spatially referenced information in providing management advice. The model provided evidence that, even on a spatial scale, fishing mortality is significantly correlated to fishing effort. Areas of high levels of spawner biomass are noted, all of which corresponded to those geographic areas with a combination of low fishing effort and high adult biomass.
- Full Text:
- Date Issued: 2000
Interaction between iron (II) tetrasulfophthalocyanine and the neurotransmitters, serotonin and dopamine
- Oni, Joshua, Nyokong, Tebello
- Authors: Oni, Joshua , Nyokong, Tebello
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293223 , vital:57066 , xlink:href="https://doi.org/10.1016/S0277-5387(00)00421-6"
- Description: This work reports on the kinetics of interaction of iron(II) tetrasulfophthalocyanine, [FeTSPc]4−, with dopamine (DA) and serotonin (5-HT). The interaction results in the coordination of dopamine and serotonin to [FeTSPc]4−, followed by internal electron transfer and the formation of [(DA+)FeITSPc]4− and [(5-HT+) FeITSPc]4− complexes, respectively. The rate constants for the coordination of dopamine or serotonin to [FeTSPc]4− and the formation of the FeITSPc species were found to be kf=6.8 and 9.3 dm3 mol−1 s−1, respectively. The equilibrium constants were 2.2×103 and 1.5×103 dm3 mol−1, respectively, for the interaction of dopamine or serotonin to [FeTSPc]4−.
- Full Text:
- Date Issued: 2000
- Authors: Oni, Joshua , Nyokong, Tebello
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293223 , vital:57066 , xlink:href="https://doi.org/10.1016/S0277-5387(00)00421-6"
- Description: This work reports on the kinetics of interaction of iron(II) tetrasulfophthalocyanine, [FeTSPc]4−, with dopamine (DA) and serotonin (5-HT). The interaction results in the coordination of dopamine and serotonin to [FeTSPc]4−, followed by internal electron transfer and the formation of [(DA+)FeITSPc]4− and [(5-HT+) FeITSPc]4− complexes, respectively. The rate constants for the coordination of dopamine or serotonin to [FeTSPc]4− and the formation of the FeITSPc species were found to be kf=6.8 and 9.3 dm3 mol−1 s−1, respectively. The equilibrium constants were 2.2×103 and 1.5×103 dm3 mol−1, respectively, for the interaction of dopamine or serotonin to [FeTSPc]4−.
- Full Text:
- Date Issued: 2000
Interaction of nitric oxide with cobalt (II) tetrasulfophthalocyanine
- Vilakazi, Sibulelo, Nyokong, Tebello
- Authors: Vilakazi, Sibulelo , Nyokong, Tebello
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293235 , vital:57067 , xlink:href="https://doi.org/10.1016/S0277-5387(99)00373-3"
- Description: The interaction of nitric oxide (NO) with cobalt(II) tetrasulfophthalocyanine [Co(II)TSPc]4−) has been studied. Coordination of NO is accompanied by electron transfer from the central metal in [Co(II)TSPc]4−, the resulting complex being represented as [(NO−)Co(III)TSPc]4−. The rate constant for the formation of this species is kf=142±7 dm3 mol−1 s−1 and an equilibrium constant of 3.0±0.5×105 dm3 mol−1 was obtained. When adsorbed to a glassy carbon electrode, [Co(II)TSPc]4− catalyses the oxidation and reduction of NO, with a detection limit of the order of 10−9 mol dm−3. Ammonia and hydroxylamine are some of the reduction products obtained for the reduction of NO on [Co(II)TSPc]4−-modified glassy carbon electrodes.
- Full Text:
- Date Issued: 2000
- Authors: Vilakazi, Sibulelo , Nyokong, Tebello
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293235 , vital:57067 , xlink:href="https://doi.org/10.1016/S0277-5387(99)00373-3"
- Description: The interaction of nitric oxide (NO) with cobalt(II) tetrasulfophthalocyanine [Co(II)TSPc]4−) has been studied. Coordination of NO is accompanied by electron transfer from the central metal in [Co(II)TSPc]4−, the resulting complex being represented as [(NO−)Co(III)TSPc]4−. The rate constant for the formation of this species is kf=142±7 dm3 mol−1 s−1 and an equilibrium constant of 3.0±0.5×105 dm3 mol−1 was obtained. When adsorbed to a glassy carbon electrode, [Co(II)TSPc]4− catalyses the oxidation and reduction of NO, with a detection limit of the order of 10−9 mol dm−3. Ammonia and hydroxylamine are some of the reduction products obtained for the reduction of NO on [Co(II)TSPc]4−-modified glassy carbon electrodes.
- Full Text:
- Date Issued: 2000
Interaction of the neurotransmitter acetylcholine with aluminium, calcium and sodium
- Matlaba, Pulane M, Daya, Santy, Nyokong, Tebello
- Authors: Matlaba, Pulane M , Daya, Santy , Nyokong, Tebello
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293246 , vital:57068 , xlink:href="https://doi.org/10.1211/146080800128735890"
- Description: Binding of aluminium to acetylcholine has important biological implications particularly in Alzheimer's disease. An electrochemical technique, adsorptive cathodic stripping voltammetry, has been employed in this study to investigate the in-situ formation of a complex between aluminium and acetylcholine. The stability of the resulting complex was compared with that of the in-situ complexes formed between acetylcholine and sodium or calcium. From the shifts in the reduction potential of the metals on addition of acetylcholine it is concluded that a strong complex is formed between acetylcholine and aluminium. Much weaker complexes are formed between calcium or sodium and acetylcholine. These results have important implications in the aetiology of Alzheimer's disease-in which brain aluminium concentrations are known to be high and brain cholinergic function is lower than normal.
- Full Text:
- Date Issued: 2000
- Authors: Matlaba, Pulane M , Daya, Santy , Nyokong, Tebello
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293246 , vital:57068 , xlink:href="https://doi.org/10.1211/146080800128735890"
- Description: Binding of aluminium to acetylcholine has important biological implications particularly in Alzheimer's disease. An electrochemical technique, adsorptive cathodic stripping voltammetry, has been employed in this study to investigate the in-situ formation of a complex between aluminium and acetylcholine. The stability of the resulting complex was compared with that of the in-situ complexes formed between acetylcholine and sodium or calcium. From the shifts in the reduction potential of the metals on addition of acetylcholine it is concluded that a strong complex is formed between acetylcholine and aluminium. Much weaker complexes are formed between calcium or sodium and acetylcholine. These results have important implications in the aetiology of Alzheimer's disease-in which brain aluminium concentrations are known to be high and brain cholinergic function is lower than normal.
- Full Text:
- Date Issued: 2000
May essential provisions of a contract be determined by one of the parties alone
- Kerr, Alistair J, Glover, Graham B
- Authors: Kerr, Alistair J , Glover, Graham B
- Date: 2000
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70912 , vital:29759 , https://heinonline.org/HOL/Page?handle=hein.journals/soaf117&id=211&collection=journals&index=
- Description: When the Supreme Court of Appeal raises a question but does not answer it, what it says can be interpreted as an invitation to all those interested in the topic to discuss it. This note is a response to such an invitation in NBS Boland Bank v One Berg River Drive CC, Deeb v ABSA Bank Ltd, Friedman v Standard Bank of South Africa Ltd 1999 (4) SA 928 (SCA);[1999] 4 All SA 183, hereinafter referred to as the NBS Boland Bank case.
- Full Text: false
- Date Issued: 2000
- Authors: Kerr, Alistair J , Glover, Graham B
- Date: 2000
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70912 , vital:29759 , https://heinonline.org/HOL/Page?handle=hein.journals/soaf117&id=211&collection=journals&index=
- Description: When the Supreme Court of Appeal raises a question but does not answer it, what it says can be interpreted as an invitation to all those interested in the topic to discuss it. This note is a response to such an invitation in NBS Boland Bank v One Berg River Drive CC, Deeb v ABSA Bank Ltd, Friedman v Standard Bank of South Africa Ltd 1999 (4) SA 928 (SCA);[1999] 4 All SA 183, hereinafter referred to as the NBS Boland Bank case.
- Full Text: false
- Date Issued: 2000
Melatonin alters the photodegradation of paracetamol
- Anoopkumar-Dukie, Shailendra, Glass, Beverley D, Walker, Roderick B, Daya, Santylal
- Authors: Anoopkumar-Dukie, Shailendra , Glass, Beverley D , Walker, Roderick B , Daya, Santylal
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184357 , vital:44211 , xlink:href="https://doi.org/10.1211/146080800128735755"
- Description: The effects of melatonin, a known free-radical scavenger, on paracetamol in the presence of UV irradiation was studied by use of HPLC. The experiments were performed in air and nitrogen. The results show that the rate of photodegradation of melatonin is faster in air than in nitrogen whereas that of paracetamol is similar in air and nitrogen. When the two drugs were combined, melatonin retarded the degradation of paracetamol for up to 6h in the presence of nitrogen. However, in the presence of air melatonin rapidly enhances the photodegradation of paracetamol. This study shows that a combination of melatonin and paracetamol in the presence of air and UV irradiation can lead to rapid inactivation of both agents, thus raising important concerns about the possible use of melatonin as sunscreen
- Full Text:
- Date Issued: 2000
- Authors: Anoopkumar-Dukie, Shailendra , Glass, Beverley D , Walker, Roderick B , Daya, Santylal
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184357 , vital:44211 , xlink:href="https://doi.org/10.1211/146080800128735755"
- Description: The effects of melatonin, a known free-radical scavenger, on paracetamol in the presence of UV irradiation was studied by use of HPLC. The experiments were performed in air and nitrogen. The results show that the rate of photodegradation of melatonin is faster in air than in nitrogen whereas that of paracetamol is similar in air and nitrogen. When the two drugs were combined, melatonin retarded the degradation of paracetamol for up to 6h in the presence of nitrogen. However, in the presence of air melatonin rapidly enhances the photodegradation of paracetamol. This study shows that a combination of melatonin and paracetamol in the presence of air and UV irradiation can lead to rapid inactivation of both agents, thus raising important concerns about the possible use of melatonin as sunscreen
- Full Text:
- Date Issued: 2000
Photocatalytic properties of neodymium diphthalocyanine towards the transformation of 4-chlorophenol
- Nensala, Ngudiankama, Nyokong, Tebello
- Authors: Nensala, Ngudiankama , Nyokong, Tebello
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:58491 , xlink:href="https://doi.org/10.1016/S1381-1169(00)00283-1"
- Description: Photolysis of aqueous solutions of 4-chlorophenol (4-Cp) in the presence of solid neodymium diphthalocyanine ([Pc(−2)NdPc(−2)]−) and oxygen using visible and ultraviolet (UV) radiation resulted in the formation of a number of products. For photolysis in the visible region, phenol, benzoquinone, hydroquinone were observed as intermediates and 4-chlorocatechol (4-CC) as the main product; intermediates similar to those observed for visible photolysis were obtained. Langmuir–Hinshelwood kinetic model was used for treatment of photochemical data.
- Full Text:
- Date Issued: 2000
Photocatalytic properties of neodymium diphthalocyanine towards the transformation of 4-chlorophenol
- Authors: Nensala, Ngudiankama , Nyokong, Tebello
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:58491 , xlink:href="https://doi.org/10.1016/S1381-1169(00)00283-1"
- Description: Photolysis of aqueous solutions of 4-chlorophenol (4-Cp) in the presence of solid neodymium diphthalocyanine ([Pc(−2)NdPc(−2)]−) and oxygen using visible and ultraviolet (UV) radiation resulted in the formation of a number of products. For photolysis in the visible region, phenol, benzoquinone, hydroquinone were observed as intermediates and 4-chlorocatechol (4-CC) as the main product; intermediates similar to those observed for visible photolysis were obtained. Langmuir–Hinshelwood kinetic model was used for treatment of photochemical data.
- Full Text:
- Date Issued: 2000