Metallophthalocyanine Based Carbon Paste Electrodes for the Determination of 2′, 3′‐Dideoxyinosine
- Ozoemena, Kenneth I, Stefan-van Staden, Raluca-Ioana, Nyokong, Tebello
- Authors: Ozoemena, Kenneth I , Stefan-van Staden, Raluca-Ioana , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263430 , vital:53627 , xlink:href="https://doi.org/10.1002/elan.200904581"
- Description: Novel electrochemical sensors based on carbon paste impregnated with metallopthalocyanine (MPc, M=Co, Fe) complexes, have been constructed for the assay of anti-HIV drug 2′,3′-dideoxyinosine (didanosine, DDI). Both modified electrodes showed electrocatalytic activity towards the oxidation of dideoxyinosine in phosphate buffer pH 7.4 with a working concentration range of 10−6–10−4 mol/L and a detection limit of 10−7 mol/L magnitude order. The sensor proved to be highly reliable for the assay of the purity of DDI - raw material as well as for the uniformity content test of Videx tablets.
- Full Text:
- Date Issued: 2009
- Authors: Ozoemena, Kenneth I , Stefan-van Staden, Raluca-Ioana , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263430 , vital:53627 , xlink:href="https://doi.org/10.1002/elan.200904581"
- Description: Novel electrochemical sensors based on carbon paste impregnated with metallopthalocyanine (MPc, M=Co, Fe) complexes, have been constructed for the assay of anti-HIV drug 2′,3′-dideoxyinosine (didanosine, DDI). Both modified electrodes showed electrocatalytic activity towards the oxidation of dideoxyinosine in phosphate buffer pH 7.4 with a working concentration range of 10−6–10−4 mol/L and a detection limit of 10−7 mol/L magnitude order. The sensor proved to be highly reliable for the assay of the purity of DDI - raw material as well as for the uniformity content test of Videx tablets.
- Full Text:
- Date Issued: 2009
Microsatellite markers for the roman, Chrysoblephus laticeps (Teleostei: Sparidae), an overexploited seabream from South Africa
- Teske, Peter R, Cowley, Paul D, Forget, Fabian R, Beheregaray, Luciano B
- Authors: Teske, Peter R , Cowley, Paul D , Forget, Fabian R , Beheregaray, Luciano B
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445690 , vital:74414 , https://doi.org/10.1111/j.1755-0998.2009.02595.x
- Description: Eleven polymorphic microsatellite loci were developed from an enrichment library of the roman, Chrysoblephus laticeps, and characterized for 40 individuals collected in Africa's largest and oldest Marine Protected Area (MPA), the Tsitsikamma National Park. The number of alleles per locus ranged from three to 19, and heterozygosities ranged from 0.20 to 0.85. A significant departure from Hardy–Weinberg equilibrium was detected for one locus, and linkage disequilibrium was identified among three pairs of loci. The markers will be useful to detect whether populations resident in MPAs along the South African coast are genetically connected, and whether there is spillover of recruits into adjacent exploited areas.
- Full Text:
- Date Issued: 2009
- Authors: Teske, Peter R , Cowley, Paul D , Forget, Fabian R , Beheregaray, Luciano B
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445690 , vital:74414 , https://doi.org/10.1111/j.1755-0998.2009.02595.x
- Description: Eleven polymorphic microsatellite loci were developed from an enrichment library of the roman, Chrysoblephus laticeps, and characterized for 40 individuals collected in Africa's largest and oldest Marine Protected Area (MPA), the Tsitsikamma National Park. The number of alleles per locus ranged from three to 19, and heterozygosities ranged from 0.20 to 0.85. A significant departure from Hardy–Weinberg equilibrium was detected for one locus, and linkage disequilibrium was identified among three pairs of loci. The markers will be useful to detect whether populations resident in MPAs along the South African coast are genetically connected, and whether there is spillover of recruits into adjacent exploited areas.
- Full Text:
- Date Issued: 2009
Mobile monitors: protecting the will of the people
- Authors: Dugmore, Harry
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159377 , vital:40292 , https://hdl.handle.net/10520/EJC139912
- Description: The use of mobile phone technology in recent African elections has empowered citizens, allowing them to put in place the checks and balances needed to make elections freer and fairer in Africa - and elsewhere in the world, writes Harry Dugmore.
- Full Text:
- Date Issued: 2009
- Authors: Dugmore, Harry
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159377 , vital:40292 , https://hdl.handle.net/10520/EJC139912
- Description: The use of mobile phone technology in recent African elections has empowered citizens, allowing them to put in place the checks and balances needed to make elections freer and fairer in Africa - and elsewhere in the world, writes Harry Dugmore.
- Full Text:
- Date Issued: 2009
Models of development for blowfly sister species Chrysomya chloropyga and Chrysomya putoria
- Richards, Cameron S, Crous, Kendall L, Villet, Martin H
- Authors: Richards, Cameron S , Crous, Kendall L , Villet, Martin H
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:73967 , https://doi.org/10.1111/j.1365-2915.2008.00767.x
- Description: Developmental curves for the sister species Chrysomya chloropyga (Wiedemann, 1818) and Chrysomya putoria (Wiedemann, 1830) (Diptera: Calliphoridae) were established at eight and 10 different constant temperatures, respectively, using developmental landmarks and body length as measures of age. The thermal summation constants (K) and developmental threshold (D0) were calculated for five developmental landmarks using a previously described method. Isomorphen and isomegalen diagrams were also constructed for the purpose of estimating postmortem intervals (PMIs). Chrysomya chloropyga had an average developmental threshold value (D0) of 10.91 °C (standard error [SE] = 0.94 °C, n = 5), significantly lower than that of C. putoria (13.42 °C, SE = 0.45 °C, n = 5) (paired t‐test: t = − 4.63, d.f. = 8, P 0.00). Similarly, K values for C. chloropyga were larger than those for C. putoria for all developmental events except onset of the wandering phase. These are the first data that can be used to calculate minimum PMIs and predict population growth of C. chloropyga and C. putoria in Africa; the data indicate that developmental data for one of these species cannot be used as surrogate data for the sister species.
- Full Text:
- Date Issued: 2009
- Authors: Richards, Cameron S , Crous, Kendall L , Villet, Martin H
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:73967 , https://doi.org/10.1111/j.1365-2915.2008.00767.x
- Description: Developmental curves for the sister species Chrysomya chloropyga (Wiedemann, 1818) and Chrysomya putoria (Wiedemann, 1830) (Diptera: Calliphoridae) were established at eight and 10 different constant temperatures, respectively, using developmental landmarks and body length as measures of age. The thermal summation constants (K) and developmental threshold (D0) were calculated for five developmental landmarks using a previously described method. Isomorphen and isomegalen diagrams were also constructed for the purpose of estimating postmortem intervals (PMIs). Chrysomya chloropyga had an average developmental threshold value (D0) of 10.91 °C (standard error [SE] = 0.94 °C, n = 5), significantly lower than that of C. putoria (13.42 °C, SE = 0.45 °C, n = 5) (paired t‐test: t = − 4.63, d.f. = 8, P 0.00). Similarly, K values for C. chloropyga were larger than those for C. putoria for all developmental events except onset of the wandering phase. These are the first data that can be used to calculate minimum PMIs and predict population growth of C. chloropyga and C. putoria in Africa; the data indicate that developmental data for one of these species cannot be used as surrogate data for the sister species.
- Full Text:
- Date Issued: 2009
Mulch tower treatment system for greywater reuse Part II: destructive testing and effluent treatment
- Tandlich, Roman, Zuma, Bongumusa M, Whittington-Jones, Kevin J, Burgess, Jo E
- Authors: Tandlich, Roman , Zuma, Bongumusa M , Whittington-Jones, Kevin J , Burgess, Jo E
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71547 , vital:29863 , https://doi.org/10.1016/j.desal.2008.03.031
- Description: The mulch tower (MT) system described in Part I was tested to failure to determine its range of operating conditions. An increase in the influent temperature led to a statistically significant release of components of the chemical oxygen demand (COD) and the five day biochemical oxygen demand (BOD5), as well as phosphates from the MT system. Heterotrophic plate count (HPC) of the mulch layer dropped from 1.2 (± 0.6) × 106/g dry weight to 1.5 (± 0.3) × 105/g dry weight of the mulch layer with increases of the influent temperature. This indicates that the increase in influent temperature killed off some of the active biomass in the MT biofilm. After a five day drying period under active aeration, the MT system retained the ability to remove COD, total suspended solids (TSS), and nitrates. Greywater treatment by the MT system became impossible after a 48 day drying period under active aeration. Chlorination of the simulated MT effluent with a mixture of sodium dichloroisocyanurate and trichloroisocyanuric acid decreased the faecal coliform concentrations (FC) and the total coliform concentrations (TC) below 800 CFUs/100 ml within 65 h. Beyond 65 h, the pH of the effluent became highly acidic. To maintain optimum performance influent should be fed into the MT system at least once every 5 days, sufficient aeration should be guaranteed, and the MT effluent should be chlorinated for 65 h to eliminate all pathogens before any reuse.
- Full Text: false
- Date Issued: 2009
Mulch tower treatment system for greywater reuse Part II: destructive testing and effluent treatment
- Authors: Tandlich, Roman , Zuma, Bongumusa M , Whittington-Jones, Kevin J , Burgess, Jo E
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71547 , vital:29863 , https://doi.org/10.1016/j.desal.2008.03.031
- Description: The mulch tower (MT) system described in Part I was tested to failure to determine its range of operating conditions. An increase in the influent temperature led to a statistically significant release of components of the chemical oxygen demand (COD) and the five day biochemical oxygen demand (BOD5), as well as phosphates from the MT system. Heterotrophic plate count (HPC) of the mulch layer dropped from 1.2 (± 0.6) × 106/g dry weight to 1.5 (± 0.3) × 105/g dry weight of the mulch layer with increases of the influent temperature. This indicates that the increase in influent temperature killed off some of the active biomass in the MT biofilm. After a five day drying period under active aeration, the MT system retained the ability to remove COD, total suspended solids (TSS), and nitrates. Greywater treatment by the MT system became impossible after a 48 day drying period under active aeration. Chlorination of the simulated MT effluent with a mixture of sodium dichloroisocyanurate and trichloroisocyanuric acid decreased the faecal coliform concentrations (FC) and the total coliform concentrations (TC) below 800 CFUs/100 ml within 65 h. Beyond 65 h, the pH of the effluent became highly acidic. To maintain optimum performance influent should be fed into the MT system at least once every 5 days, sufficient aeration should be guaranteed, and the MT effluent should be chlorinated for 65 h to eliminate all pathogens before any reuse.
- Full Text: false
- Date Issued: 2009
Mulch tower treatment system Part I: Overall performance in greywater treatment
- Zuma, Bongumusa M, Tandlich, Roman, Whittington-Jones, Kevin J, Burgess, Jo E
- Authors: Zuma, Bongumusa M , Tandlich, Roman , Whittington-Jones, Kevin J , Burgess, Jo E
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71537 , vital:29862 , https://doi.org/10.1016/j.desal.2008.03.030
- Description: A mulch tower (MT) system for greywater treatment is introduced in this paper. Materials used to assemble the MT system included mulch, coarse sand, fine and coarse gravel. Limited removal efficiency of the MT system was demonstrated for alkalinity, total hardness, pH, Cl–, PO43–, NH4+, and SO42–, with the estimated cumulative removals ranging from 7 to 12%. Intermediate removal efficiency was observed for chemical oxygen demand (COD), NO3–, and S2– with the estimated cumulative removals ranging from 24 to 28%. The highest removal efficiency was observed for the total suspended solids (TSS) with the estimated cumulative removal equal to 52%. Given the minute residence time in the MT system, the results obtained were promising and justify scale-up studies for potential on-site applications. The MT effluent did not meet hygienic norms with respect to the faecal coliform concentration (FC) and the total coliform concentration (TC), and further effluent treatment is required before any discharge or reuse of the treated greywater. Further research should focus on characterisation of the microbial community of the MT, and the fate of Cl–, PO43–, NH4+, and SO42–.
- Full Text: false
- Date Issued: 2009
- Authors: Zuma, Bongumusa M , Tandlich, Roman , Whittington-Jones, Kevin J , Burgess, Jo E
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71537 , vital:29862 , https://doi.org/10.1016/j.desal.2008.03.030
- Description: A mulch tower (MT) system for greywater treatment is introduced in this paper. Materials used to assemble the MT system included mulch, coarse sand, fine and coarse gravel. Limited removal efficiency of the MT system was demonstrated for alkalinity, total hardness, pH, Cl–, PO43–, NH4+, and SO42–, with the estimated cumulative removals ranging from 7 to 12%. Intermediate removal efficiency was observed for chemical oxygen demand (COD), NO3–, and S2– with the estimated cumulative removals ranging from 24 to 28%. The highest removal efficiency was observed for the total suspended solids (TSS) with the estimated cumulative removal equal to 52%. Given the minute residence time in the MT system, the results obtained were promising and justify scale-up studies for potential on-site applications. The MT effluent did not meet hygienic norms with respect to the faecal coliform concentration (FC) and the total coliform concentration (TC), and further effluent treatment is required before any discharge or reuse of the treated greywater. Further research should focus on characterisation of the microbial community of the MT, and the fate of Cl–, PO43–, NH4+, and SO42–.
- Full Text: false
- Date Issued: 2009
Nathaniel Merriman’s lecture: “Shakspeare, as Bearing on English History”
- Authors: Wright, Laurence
- Date: 2009
- Language: English
- Type: text , article
- Identifier: vital:7060 , http://hdl.handle.net/10962/d1007424 , http://hdl.handle.net/10520/EJC48132
- Description: preprint , “Shakspeare, as Bearing on English History” is the second of two lectures on Shakespeare given by Archdeacon Nathaniel Merriman in Grahamstown in 1857. The first was delivered in the Court House on the 2nd September 1857, and the second two months later, on Friday 6th November that same year, again in the Court House. The lecture was published in 1858. An article placing the lectures in their local context appeared in Shakespeare in Southern Africa 20 (2008): 25-37, accompanying an annotated edition of the first lecture, “On the Study of Shakspeare”. Readers desiring details of the editorial principles adopted in producing annotated editions of the two lectures are referred to the introductory material prefacing the first lecture.
- Full Text:
- Date Issued: 2009
- Authors: Wright, Laurence
- Date: 2009
- Language: English
- Type: text , article
- Identifier: vital:7060 , http://hdl.handle.net/10962/d1007424 , http://hdl.handle.net/10520/EJC48132
- Description: preprint , “Shakspeare, as Bearing on English History” is the second of two lectures on Shakespeare given by Archdeacon Nathaniel Merriman in Grahamstown in 1857. The first was delivered in the Court House on the 2nd September 1857, and the second two months later, on Friday 6th November that same year, again in the Court House. The lecture was published in 1858. An article placing the lectures in their local context appeared in Shakespeare in Southern Africa 20 (2008): 25-37, accompanying an annotated edition of the first lecture, “On the Study of Shakspeare”. Readers desiring details of the editorial principles adopted in producing annotated editions of the two lectures are referred to the introductory material prefacing the first lecture.
- Full Text:
- Date Issued: 2009
NGOs and rural movements in contemporary South Africa
- Authors: Helliker, Kirk D
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71252 , vital:29823 , https://doi.org/10.1080/02533952.2013.806415
- Description: This article provides a critical examination of relationships between non-governmental organisations (NGOs) and rural movements in post-apartheid South Africa, particularly with regard to the possible subordination of movements to NGOs. In discussing NGOs as a particular organisational form, and in reviewing some arguments pertaining to NGOs and rural movements globally, I explore whether NGOs in South Africa have a progressive role to play in agrarian transformation.
- Full Text:
- Date Issued: 2009
- Authors: Helliker, Kirk D
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71252 , vital:29823 , https://doi.org/10.1080/02533952.2013.806415
- Description: This article provides a critical examination of relationships between non-governmental organisations (NGOs) and rural movements in post-apartheid South Africa, particularly with regard to the possible subordination of movements to NGOs. In discussing NGOs as a particular organisational form, and in reviewing some arguments pertaining to NGOs and rural movements globally, I explore whether NGOs in South Africa have a progressive role to play in agrarian transformation.
- Full Text:
- Date Issued: 2009
Nine Notes on Lisbon
- Authors: Krueger, Anton
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229807 , vital:49712 , xlink:href="https://hdl.handle.net/10520/EJC47812"
- Full Text:
- Date Issued: 2009
- Authors: Krueger, Anton
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229807 , vital:49712 , xlink:href="https://hdl.handle.net/10520/EJC47812"
- Full Text:
- Date Issued: 2009
Of fences and peace between neighbours
- Authors: Krüger, Rósaan
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68909 , vital:29338 , https://hdl.handle.net/10520/EJC85309
- Description: Publisher version , The speaker in the poem "Mending Wall" by American poet Robert Frost questions the wisdom of the saying that "Good Fences Make Good Neighbo[u]rs" (1914 North of Boston lines 27 and 45). The walls or fences referred to in the poem represent more than just physical barriers separating adjacent premises; the speaker sees them as representing obstacles to communication and friendship between individuals. Seen from the perspective of the speaker, a fence or wall is a "bad" thing. But the speaker is but one of the parties to the neighbourly relationship. For the speaker's neighbour, a wall or a fence is "a protector of privacy" (Watson "Frost's Wall : The View from the Other Side" 1971 44 The New England Quarterly 653 655). Thus there are two views on walls or fences: they can be seen negatively as obstructing good relations, or positively as dividers that secure good relations between neighbours by separating them and protecting their privacy rights.
- Full Text: false
- Date Issued: 2009
- Authors: Krüger, Rósaan
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68909 , vital:29338 , https://hdl.handle.net/10520/EJC85309
- Description: Publisher version , The speaker in the poem "Mending Wall" by American poet Robert Frost questions the wisdom of the saying that "Good Fences Make Good Neighbo[u]rs" (1914 North of Boston lines 27 and 45). The walls or fences referred to in the poem represent more than just physical barriers separating adjacent premises; the speaker sees them as representing obstacles to communication and friendship between individuals. Seen from the perspective of the speaker, a fence or wall is a "bad" thing. But the speaker is but one of the parties to the neighbourly relationship. For the speaker's neighbour, a wall or a fence is "a protector of privacy" (Watson "Frost's Wall : The View from the Other Side" 1971 44 The New England Quarterly 653 655). Thus there are two views on walls or fences: they can be seen negatively as obstructing good relations, or positively as dividers that secure good relations between neighbours by separating them and protecting their privacy rights.
- Full Text: false
- Date Issued: 2009
On location: Narratives of the South African city of the late 1940s and 1950s in film and literature
- Authors: Baines, Gary F
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125397 , vital:35779 , https://doi.10.1080/02582470308671922
- Description: This article is about narratives, about the forms and meanings constructed by South African storytellers, especially writers and filmmakers. It examines the relationships between examples of these two different narrative forms of literature (fiction and non-fiction) and feature film. Following Turner, the point of departure is that the study of narrative has the potential to provide a framework within which such a two pronged approach can be undertaken. This is not to say that the production of meaning takes place within an exclusive literary or cinematic context. Rather, this approach will allow us to obtain a fuller picture of the narrative of the South African city than is possible by concentrating on one medium. It is based on the premise that narratives are ultimately produced by culture; thus these cultural constructions generate meanings, take on a significance, and assume forms that are articufations of the values, beliefs -the ideology - of the culture.' Literature and film offer specific forms for such narratives. By adopting an interdisciplinary approach which borrows insights from literary and film studies, this article attempts to make a contribution to the fledgling field of South African cultural studies.
- Full Text:
- Date Issued: 2009
On location: Narratives of the South African city of the late 1940s and 1950s in film and literature
- Authors: Baines, Gary F
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125397 , vital:35779 , https://doi.10.1080/02582470308671922
- Description: This article is about narratives, about the forms and meanings constructed by South African storytellers, especially writers and filmmakers. It examines the relationships between examples of these two different narrative forms of literature (fiction and non-fiction) and feature film. Following Turner, the point of departure is that the study of narrative has the potential to provide a framework within which such a two pronged approach can be undertaken. This is not to say that the production of meaning takes place within an exclusive literary or cinematic context. Rather, this approach will allow us to obtain a fuller picture of the narrative of the South African city than is possible by concentrating on one medium. It is based on the premise that narratives are ultimately produced by culture; thus these cultural constructions generate meanings, take on a significance, and assume forms that are articufations of the values, beliefs -the ideology - of the culture.' Literature and film offer specific forms for such narratives. By adopting an interdisciplinary approach which borrows insights from literary and film studies, this article attempts to make a contribution to the fledgling field of South African cultural studies.
- Full Text:
- Date Issued: 2009
On Moving House
- Authors: Krueger, Anton
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229785 , vital:49710 , xlink:href="https://hdl.handle.net/10520/EJC47812"
- Full Text:
- Date Issued: 2009
- Authors: Krueger, Anton
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229785 , vital:49710 , xlink:href="https://hdl.handle.net/10520/EJC47812"
- Full Text:
- Date Issued: 2009
Opposing responses elicited by positively charged phthalocyanines in the presence of CdTe quantum dots
- Moeno, Sharon, Nyokong, Tebello
- Authors: Moeno, Sharon , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/264506 , vital:53740 , xlink:href="https://doi.org/10.1016/j.jphotochem.2008.10.027"
- Description: Tetrapositively charged phthalocyanines and CdTe quantum dots (QDs) capped with thioglycolic acid (TGA) and mercaptopropionic acid (MPA) were synthesized. The response of the tetrapositively charged zinc phthalocyanines in the presence of quantum dots was studied. Aggregation and charge transfer were observed for [tetramethyl-2,(3)-[tetra-(2-mercaptopyridinephthalocyaninato)]zinc(II)]4+ (TmTMPyZnPc), however aggregation proved to be the more prominent process of the two. Fluorescence resonance energy transfer (FRET) was observed with [tetramethyl-2,(3)-[tetra-(2- pyridyloxyphthalocyaninato)]zinc(II)]4+ (TmTPyZnPc). In the FRET study the efficiency of FRET with TmTPyZnPc was determined to be 21% for both MPA and TGA capped CdTe QDs. For the charge transfer study the fluorescence of the quantum dots was quenched by the TmTMPyZnPc used, and from these quenching studies the quenching constants, binding constants and number of binding sites on the quantum dots were determined.
- Full Text:
- Date Issued: 2009
- Authors: Moeno, Sharon , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/264506 , vital:53740 , xlink:href="https://doi.org/10.1016/j.jphotochem.2008.10.027"
- Description: Tetrapositively charged phthalocyanines and CdTe quantum dots (QDs) capped with thioglycolic acid (TGA) and mercaptopropionic acid (MPA) were synthesized. The response of the tetrapositively charged zinc phthalocyanines in the presence of quantum dots was studied. Aggregation and charge transfer were observed for [tetramethyl-2,(3)-[tetra-(2-mercaptopyridinephthalocyaninato)]zinc(II)]4+ (TmTMPyZnPc), however aggregation proved to be the more prominent process of the two. Fluorescence resonance energy transfer (FRET) was observed with [tetramethyl-2,(3)-[tetra-(2- pyridyloxyphthalocyaninato)]zinc(II)]4+ (TmTPyZnPc). In the FRET study the efficiency of FRET with TmTPyZnPc was determined to be 21% for both MPA and TGA capped CdTe QDs. For the charge transfer study the fluorescence of the quantum dots was quenched by the TmTMPyZnPc used, and from these quenching studies the quenching constants, binding constants and number of binding sites on the quantum dots were determined.
- Full Text:
- Date Issued: 2009
Paper recycling patterns and potential interventions in the education sector: A case study of paper streams at Rhodes University, South Africa
- Amutenya, N, Shackleton, Charlie M, Whittington-Jones, Kevin J
- Authors: Amutenya, N , Shackleton, Charlie M , Whittington-Jones, Kevin J
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181180 , vital:43705 , xlink:href="https://doi.org/10.1016/j.resconrec.2008.12.001"
- Description: This paper considers the use of paper by academics and student computer laboratories at Rhodes University as a basis for identifying areas to reduce the amounts used and increase rates of recycling. A sample of 50 academic staff monitored the volume and purpose of the paper they used over 5 months, and the procurement officers in all the academic departments were interviewed regarding the total amount of paper used per academic department. Mean use was 34 ± 20 new sheets of paper per working day, of which 3% were trashed, 15% were kept for later use (as scrap or printed on the opposite side) and 79% were given out as notes to students, filed as records or posted out as mail to other departments or institutions. There was a significant relationship between number of students served by a department and the overall demand for paper, as well the number of staff per department and the number of recycling bins. The university could save approximately US$ 7000 per year for every 10% reduction in current use of paper (12,784 reams/year). Reduction in paper usage could be achieved through an increase in re-use of paper, printing handouts for students on both sides of each sheet of paper and by investing in printers that are capable of printing on both sides of a sheet of paper. Double-sided printers are only 20–25% more expensive than single-sided ones, but will potentially reduce paper usage by half. A 40% reduction would save the university approximately US $ 20,000 per year in direct costs, and more in reduced waste streams, as well as help promote the environmental image of the university. On a per unit basis, the higher costs for a double-sided printer in offices would be repaid in 9 months or less through reduced paper use.
- Full Text:
- Date Issued: 2009
- Authors: Amutenya, N , Shackleton, Charlie M , Whittington-Jones, Kevin J
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181180 , vital:43705 , xlink:href="https://doi.org/10.1016/j.resconrec.2008.12.001"
- Description: This paper considers the use of paper by academics and student computer laboratories at Rhodes University as a basis for identifying areas to reduce the amounts used and increase rates of recycling. A sample of 50 academic staff monitored the volume and purpose of the paper they used over 5 months, and the procurement officers in all the academic departments were interviewed regarding the total amount of paper used per academic department. Mean use was 34 ± 20 new sheets of paper per working day, of which 3% were trashed, 15% were kept for later use (as scrap or printed on the opposite side) and 79% were given out as notes to students, filed as records or posted out as mail to other departments or institutions. There was a significant relationship between number of students served by a department and the overall demand for paper, as well the number of staff per department and the number of recycling bins. The university could save approximately US$ 7000 per year for every 10% reduction in current use of paper (12,784 reams/year). Reduction in paper usage could be achieved through an increase in re-use of paper, printing handouts for students on both sides of each sheet of paper and by investing in printers that are capable of printing on both sides of a sheet of paper. Double-sided printers are only 20–25% more expensive than single-sided ones, but will potentially reduce paper usage by half. A 40% reduction would save the university approximately US $ 20,000 per year in direct costs, and more in reduced waste streams, as well as help promote the environmental image of the university. On a per unit basis, the higher costs for a double-sided printer in offices would be repaid in 9 months or less through reduced paper use.
- Full Text:
- Date Issued: 2009
Passive Traffic Inspection for Automated Firewall Rule Set Generation
- Pranschke, Georg-Christian, Irwin, Barry V W, Barnett, Richard J
- Authors: Pranschke, Georg-Christian , Irwin, Barry V W , Barnett, Richard J
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428114 , vital:72487 , https://d1wqtxts1xzle7.cloudfront.net/49200001/Automated_Firewall_Rule_Set_Generation_T20160928-12076-1n830lx-libre.pdf?1475130103=andresponse-content-disposi-tion=inline%3B+filename%3DAutomated_Firewall_Rule_Set_Generation_T.pdfandExpires=1714733377andSignature=Q0miMvZNpP7c60n42m54TvFG4hIdujVJBilbpvDKquBk54RPwU22pH6-40mpmOxIFBllKUmOgZfS9SwzuiANn-AZ2bhAELyZmf2bJ5MgceaYH5wnPjX9VzP04C2BACzhO5YutUfwkysburUx-zNdiemSofx2p1DwOszXaJNauYdP8RcHQmFl8aOnkoc3kmU02eKz8WiQISntJtu5Gpo8txP-Z6f1BEzvlVGd432tndhRwpsEVWGW43~oXsdaWQu72S8pTakgKPREqaD7CUHKMXiiUBfuiSj1nFo2n4xZQlFHqbMT7TAYzBPM0GObe~kBe5s2nY6dnOMUKUsSaeTUtqA__andKey-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: The introduction of network filters and chokes such as firewalls in exist-ing operational network is often problematic, due to considerations that need to be made to minimise the interruption of existent legitimate traf-fic. This often necessitates the time consuming manual analysis of net-work traffic over a period of time in order to generate and vet the rule bases to minimise disruption of legitimate flows. To improve upon this, a system facilitating network traffic analysis and firewall rule set genera-tion is proposed. The system shall be capable to deal with the ever in-creasing traffic volumes and help to provide and maintain high uptimes. A high level overview of the design of the components is presented. Additions to the system are scoring metrics which may assist the admin-istrator to optimise the rule sets for the most efficient matching of flows, based on traffic volume, frequency or packet count. A third party pack-age-Firewall Builder-is used to target the resultant rule sets to a number of different firewall and network Filtering platforms.
- Full Text:
- Date Issued: 2009
- Authors: Pranschke, Georg-Christian , Irwin, Barry V W , Barnett, Richard J
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428114 , vital:72487 , https://d1wqtxts1xzle7.cloudfront.net/49200001/Automated_Firewall_Rule_Set_Generation_T20160928-12076-1n830lx-libre.pdf?1475130103=andresponse-content-disposi-tion=inline%3B+filename%3DAutomated_Firewall_Rule_Set_Generation_T.pdfandExpires=1714733377andSignature=Q0miMvZNpP7c60n42m54TvFG4hIdujVJBilbpvDKquBk54RPwU22pH6-40mpmOxIFBllKUmOgZfS9SwzuiANn-AZ2bhAELyZmf2bJ5MgceaYH5wnPjX9VzP04C2BACzhO5YutUfwkysburUx-zNdiemSofx2p1DwOszXaJNauYdP8RcHQmFl8aOnkoc3kmU02eKz8WiQISntJtu5Gpo8txP-Z6f1BEzvlVGd432tndhRwpsEVWGW43~oXsdaWQu72S8pTakgKPREqaD7CUHKMXiiUBfuiSj1nFo2n4xZQlFHqbMT7TAYzBPM0GObe~kBe5s2nY6dnOMUKUsSaeTUtqA__andKey-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: The introduction of network filters and chokes such as firewalls in exist-ing operational network is often problematic, due to considerations that need to be made to minimise the interruption of existent legitimate traf-fic. This often necessitates the time consuming manual analysis of net-work traffic over a period of time in order to generate and vet the rule bases to minimise disruption of legitimate flows. To improve upon this, a system facilitating network traffic analysis and firewall rule set genera-tion is proposed. The system shall be capable to deal with the ever in-creasing traffic volumes and help to provide and maintain high uptimes. A high level overview of the design of the components is presented. Additions to the system are scoring metrics which may assist the admin-istrator to optimise the rule sets for the most efficient matching of flows, based on traffic volume, frequency or packet count. A third party pack-age-Firewall Builder-is used to target the resultant rule sets to a number of different firewall and network Filtering platforms.
- Full Text:
- Date Issued: 2009
Peacekeeping in Africa: problems and prospects
- Authors: Juma, Laurence
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/129113 , vital:36219 , https://heinonline.org/HOL/P?h=hein.journals/unbotslj9amp;i=3
- Description: Against the background of an expanded need for peacekeeping, the complexity that its programmes entail, and the belief that it will endure for a long time to come, this article discusses the propriety of international peacekeeping operations, its inherent features and weaknesses in creating or preserving peace, and the role that regional organisations play, or should play, in its enhancement.
- Full Text: false
- Date Issued: 2009
- Authors: Juma, Laurence
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/129113 , vital:36219 , https://heinonline.org/HOL/P?h=hein.journals/unbotslj9amp;i=3
- Description: Against the background of an expanded need for peacekeeping, the complexity that its programmes entail, and the belief that it will endure for a long time to come, this article discusses the propriety of international peacekeeping operations, its inherent features and weaknesses in creating or preserving peace, and the role that regional organisations play, or should play, in its enhancement.
- Full Text: false
- Date Issued: 2009
Peer-to-Peer Web Services for Distributed Rural ICTs
- Wertlen, Ronald, Terzoli, Alfredo
- Authors: Wertlen, Ronald , Terzoli, Alfredo
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428508 , vital:72516 , https://www.researchgate.net/profile/Alfredo-Terzoli/publication/265184410_Peer-to-Peer_Web_Services_for_Distributed_Rural_ICTs/links/5523cb9a0cf223eed37fe0b3/Peer-to-Peer-Web-Services-for-Distributed-Rural-ICTs.pdf
- Description: In this paper we look at the context and design of a distributed web ser-vices platform called P2PMW. P2PMW uses P2P principles to automat-ically build a robust network with flexible routing and practically no ad-ministrative overhead in order to share resources between nodes. P2PMW uses open source and widely adopted standards. Our argu-ment is that the context of rural ICTs is being shaped by high speed wireless networks with limited span that we call “islands” and that the architecture we introduce is a good fit for the context. We further argue that by employing widely adopted open standards and open source software, we can speed the development of effective custom made ap-plications for marginalised rural areas.
- Full Text:
- Date Issued: 2009
- Authors: Wertlen, Ronald , Terzoli, Alfredo
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428508 , vital:72516 , https://www.researchgate.net/profile/Alfredo-Terzoli/publication/265184410_Peer-to-Peer_Web_Services_for_Distributed_Rural_ICTs/links/5523cb9a0cf223eed37fe0b3/Peer-to-Peer-Web-Services-for-Distributed-Rural-ICTs.pdf
- Description: In this paper we look at the context and design of a distributed web ser-vices platform called P2PMW. P2PMW uses P2P principles to automat-ically build a robust network with flexible routing and practically no ad-ministrative overhead in order to share resources between nodes. P2PMW uses open source and widely adopted standards. Our argu-ment is that the context of rural ICTs is being shaped by high speed wireless networks with limited span that we call “islands” and that the architecture we introduce is a good fit for the context. We further argue that by employing widely adopted open standards and open source software, we can speed the development of effective custom made ap-plications for marginalised rural areas.
- Full Text:
- Date Issued: 2009
Performance Effects of Concurrent Virtual Machine Execution in VMware Workstation 6
- Barnett, Richard J, Irwin, Barry V W
- Authors: Barnett, Richard J , Irwin, Barry V W
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429966 , vital:72655 , https://doi.org/10.1007/978-90-481-3660-5_56
- Description: The recent trend toward virtualized computing both as a means of serv-er consolidation and as a powerful desktop computing tool has lead into a wide variety of studies into the performance of hypervisor products. This study has investigated the scalability of VMware Workstation 6 on the desktop platform. We present comparative performance results for the concurrent execution of a number of virtual machines. A through statistical analysis of the performance results highlights the perfor-mance trends of different numbers of concurrent virtual machines and concludes that VMware workstation can scale in certain contexts. We find that there are different performance benefits dependant on the ap-plication and that memory intensive applications perform less effective-ly than those applications which are IO intensive. We also find that run-ning concurrent virtual machines offers a significant performance de-crease, but that the drop thereafter is less significant.
- Full Text:
- Date Issued: 2009
- Authors: Barnett, Richard J , Irwin, Barry V W
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429966 , vital:72655 , https://doi.org/10.1007/978-90-481-3660-5_56
- Description: The recent trend toward virtualized computing both as a means of serv-er consolidation and as a powerful desktop computing tool has lead into a wide variety of studies into the performance of hypervisor products. This study has investigated the scalability of VMware Workstation 6 on the desktop platform. We present comparative performance results for the concurrent execution of a number of virtual machines. A through statistical analysis of the performance results highlights the perfor-mance trends of different numbers of concurrent virtual machines and concludes that VMware workstation can scale in certain contexts. We find that there are different performance benefits dependant on the ap-plication and that memory intensive applications perform less effective-ly than those applications which are IO intensive. We also find that run-ning concurrent virtual machines offers a significant performance de-crease, but that the drop thereafter is less significant.
- Full Text:
- Date Issued: 2009
Photophysical, photochemical and electrochemical properties of water soluble silicon, titanium and zinc phthalocyanines
- Masilela, Nkosiphile, Idowu, Mopelola, Nyokong, Tebello
- Authors: Masilela, Nkosiphile , Idowu, Mopelola , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/264496 , vital:53739 , xlink:href="https://doi.org/10.1016/j.jphotochem.2008.10.009"
- Description: The photophysical, and photochemical properties of titanium, silicon and zinc octacarboxy phthalocyanine (OTiOCPc, (OH)2SiOCPc and ZnOCPc) and their tetrasulfonated counterparts (OTiTSPc, (OH)2SiTSPc and ZnTSPc) in phosphate-buffer solution (PBS), pH 10 were studied. The tetrasulfonated derivatives were also studied in the presence of a surfactant, cremophore EL (CEL) due to their high aggregation tendency in aqueous solutions. Triplet quantum yields ranged from 0.20 to 0.48 for MOCPcs and 0.32–0.65 for MTSPcs in the presence of CEL and in pH 10. High triplet lifetimes were observed for ZnTSPc (270 μs, in the presence of CEL) or ZnOCPc (130 μs) compared to values ranging from 50 to 70 μs for the rest of the complexes.
- Full Text:
- Date Issued: 2009
- Authors: Masilela, Nkosiphile , Idowu, Mopelola , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/264496 , vital:53739 , xlink:href="https://doi.org/10.1016/j.jphotochem.2008.10.009"
- Description: The photophysical, and photochemical properties of titanium, silicon and zinc octacarboxy phthalocyanine (OTiOCPc, (OH)2SiOCPc and ZnOCPc) and their tetrasulfonated counterparts (OTiTSPc, (OH)2SiTSPc and ZnTSPc) in phosphate-buffer solution (PBS), pH 10 were studied. The tetrasulfonated derivatives were also studied in the presence of a surfactant, cremophore EL (CEL) due to their high aggregation tendency in aqueous solutions. Triplet quantum yields ranged from 0.20 to 0.48 for MOCPcs and 0.32–0.65 for MTSPcs in the presence of CEL and in pH 10. High triplet lifetimes were observed for ZnTSPc (270 μs, in the presence of CEL) or ZnOCPc (130 μs) compared to values ranging from 50 to 70 μs for the rest of the complexes.
- Full Text:
- Date Issued: 2009
Photophysicochemical and fluorescence quenching studies of tetra-and octa-carboxy substituted silicon and germanium phthalocyanines
- Idowu, Mopelola, Nyokong, Tebello
- Authors: Idowu, Mopelola , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263500 , vital:53633 , xlink:href="https://doi.org/10.1016/j.jphotochem.2009.02.002"
- Description: Spectral, photophysical and photochemical properties of tetra- and octa-carboxy substituted metallophthalocyanines containing silicon and germanium as central metals ((OH)2GeTCPc, (OH)2SiTCPc, (OH)2GeOCPc and (OH)2SiOCPc) have been studied in dimethylsulfoxide (DMSO) and the trends in triplet, fluorescence, singlet oxygen quantum yields and triplet lifetimes are described for these compounds. The GePc derivatives exhibited high triplet quantum yields (ΦT = 0.79 for (OH)2GeOCPc and 0.82 for (OH)2GeTCPc compared to ΦT = 0.66 for (OH)2SiTCPc and 0.48 for (OH)2SiOCPc) due to the spin–orbit coupling induced by Ge(IV). The triplet lifetimes were higher for MOCPc (τT = 760 μs for (OH)2SiOCPc and 480 μs for (OH)2GeOCPc compared to τT = 210 μs for (OH)2SiTCPc and 260 μs for (OH)2GeTCPc). The fluorescent states of the metallophthalocyanine (MPc) complexes were effectively quenched by benzoquinone (BQ) and the quenching course was found to follow a diffusion-controlled (dynamic) bimolecular mechanism. Theoretical values of bimolecular rate constant for the interaction of the complexes with BQ were determined using the Stokes–Einstein–Smoluchowski model, and values together with the Stern–Volmer quenching constants were used in calculating the fluorescence lifetimes of the complexes.
- Full Text:
- Date Issued: 2009
- Authors: Idowu, Mopelola , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263500 , vital:53633 , xlink:href="https://doi.org/10.1016/j.jphotochem.2009.02.002"
- Description: Spectral, photophysical and photochemical properties of tetra- and octa-carboxy substituted metallophthalocyanines containing silicon and germanium as central metals ((OH)2GeTCPc, (OH)2SiTCPc, (OH)2GeOCPc and (OH)2SiOCPc) have been studied in dimethylsulfoxide (DMSO) and the trends in triplet, fluorescence, singlet oxygen quantum yields and triplet lifetimes are described for these compounds. The GePc derivatives exhibited high triplet quantum yields (ΦT = 0.79 for (OH)2GeOCPc and 0.82 for (OH)2GeTCPc compared to ΦT = 0.66 for (OH)2SiTCPc and 0.48 for (OH)2SiOCPc) due to the spin–orbit coupling induced by Ge(IV). The triplet lifetimes were higher for MOCPc (τT = 760 μs for (OH)2SiOCPc and 480 μs for (OH)2GeOCPc compared to τT = 210 μs for (OH)2SiTCPc and 260 μs for (OH)2GeTCPc). The fluorescent states of the metallophthalocyanine (MPc) complexes were effectively quenched by benzoquinone (BQ) and the quenching course was found to follow a diffusion-controlled (dynamic) bimolecular mechanism. Theoretical values of bimolecular rate constant for the interaction of the complexes with BQ were determined using the Stokes–Einstein–Smoluchowski model, and values together with the Stern–Volmer quenching constants were used in calculating the fluorescence lifetimes of the complexes.
- Full Text:
- Date Issued: 2009