Quinones and halogenated monoterpenes of algal origin show anti-proliferative effects against breast cancer cells in vitro:
- de la Mare, Jo-Anne, Lawson, Jessica C, Chiwakata, Maynard T, Beukes, Denzil R, Blatch, Gregory L, Edkins, Adrienne L
- Authors: de la Mare, Jo-Anne , Lawson, Jessica C , Chiwakata, Maynard T , Beukes, Denzil R , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165165 , vital:41214 , DOI: 10.1007/s10637-011-9788-0
- Description: Red and brown algae have been shown to produce a variety of compounds with chemotherapeutic potential. A recent report described the isolation of a range of novel polyhalogenated monoterpene compounds from the red algae Plocamium corallorhiza and Plocamium cornutum collected off the coast of South Africa, together with the previously described tetraprenylquinone, sargaquinoic acid (SQA), from the brown algae Sargassum heterophyllum. In our study, the algal compounds were screened for anti-proliferative activity against metastatic MDA-MB-231 breast cancer cells revealing that a number of compounds displayed anti-cancer activity with IC50 values in the micromolar range. A subset of the compounds was tested for differential toxicity in the MCF-7/MCF12A system and five of these, including sargaquinoic acid, were found to be at least three times more toxic to the breast cancer than the non-malignant cell line.
- Full Text:
- Date Issued: 2012
- Authors: de la Mare, Jo-Anne , Lawson, Jessica C , Chiwakata, Maynard T , Beukes, Denzil R , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165165 , vital:41214 , DOI: 10.1007/s10637-011-9788-0
- Description: Red and brown algae have been shown to produce a variety of compounds with chemotherapeutic potential. A recent report described the isolation of a range of novel polyhalogenated monoterpene compounds from the red algae Plocamium corallorhiza and Plocamium cornutum collected off the coast of South Africa, together with the previously described tetraprenylquinone, sargaquinoic acid (SQA), from the brown algae Sargassum heterophyllum. In our study, the algal compounds were screened for anti-proliferative activity against metastatic MDA-MB-231 breast cancer cells revealing that a number of compounds displayed anti-cancer activity with IC50 values in the micromolar range. A subset of the compounds was tested for differential toxicity in the MCF-7/MCF12A system and five of these, including sargaquinoic acid, were found to be at least three times more toxic to the breast cancer than the non-malignant cell line.
- Full Text:
- Date Issued: 2012
Radical thinking in South Africa’s age of retreat
- Helliker, Kirk D, Vale, Peter C J
- Authors: Helliker, Kirk D , Vale, Peter C J
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71214 , vital:29818 , https://doi.org/10.1177/0021909612442654
- Description: This article traces the rise and fall of radical praxis in South Africa and offers a critique of the prevailing practices of former Marxists under post-apartheid conditions. Western Marxism emerged in the 1970s in South Africa and Marxist activists became deeply involved in the liberation movements. With the unravelling of apartheid, the main liberation forces made a social pact with capitalist forces and former Marxists embraced a statist project. In the context of the rise of ‘new’ social movements, radical thinking of a more Libertarian kind is emerging in contemporary South Africa.
- Full Text: false
- Date Issued: 2012
- Authors: Helliker, Kirk D , Vale, Peter C J
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71214 , vital:29818 , https://doi.org/10.1177/0021909612442654
- Description: This article traces the rise and fall of radical praxis in South Africa and offers a critique of the prevailing practices of former Marxists under post-apartheid conditions. Western Marxism emerged in the 1970s in South Africa and Marxist activists became deeply involved in the liberation movements. With the unravelling of apartheid, the main liberation forces made a social pact with capitalist forces and former Marxists embraced a statist project. In the context of the rise of ‘new’ social movements, radical thinking of a more Libertarian kind is emerging in contemporary South Africa.
- Full Text: false
- Date Issued: 2012
Regular moult-breeding overlap in the Pale-winged Starling Onychognathus nabouroup
- Authors: Craig, Adrian J F K
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449518 , vital:74827 , https://www.tandfonline.com/doi/pdf/10.2989/00306525.2012.737149
- Description: In an earlier publication, with a sample consisting entirely of dated museum specimens, I concluded that, at the population level, moult-breeding overlap occurred in the Pale-winged Starling Onychognathus nabouroup, and in two other southern African Sturnidae, for which both museum skins and ringing records were available (Craig 1983). Subsequently, additional Pale-winged Starling specimens were examined in a reassessment of the subspecies that had been described, but no further analysis of the moult was undertaken (Craig 1988a). As part of a current behavioural study of this species, 58 Pale-winged Starlings were captured and colour-ringed at Augrabies Falls National Park during October 2011, and moult data were recorded for each bird following the standard scoring system for primary wing-feathers (de Beer et al. 2001). This prompted a re-examination of my earlier data, including the application of the Underhill-Zucchini model (Underhill and Zucchini 1988) to the available material.
- Full Text:
- Date Issued: 2012
- Authors: Craig, Adrian J F K
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449518 , vital:74827 , https://www.tandfonline.com/doi/pdf/10.2989/00306525.2012.737149
- Description: In an earlier publication, with a sample consisting entirely of dated museum specimens, I concluded that, at the population level, moult-breeding overlap occurred in the Pale-winged Starling Onychognathus nabouroup, and in two other southern African Sturnidae, for which both museum skins and ringing records were available (Craig 1983). Subsequently, additional Pale-winged Starling specimens were examined in a reassessment of the subspecies that had been described, but no further analysis of the moult was undertaken (Craig 1988a). As part of a current behavioural study of this species, 58 Pale-winged Starlings were captured and colour-ringed at Augrabies Falls National Park during October 2011, and moult data were recorded for each bird following the standard scoring system for primary wing-feathers (de Beer et al. 2001). This prompted a re-examination of my earlier data, including the application of the Underhill-Zucchini model (Underhill and Zucchini 1988) to the available material.
- Full Text:
- Date Issued: 2012
Remembering Jakes - Chancellor, our chancellor
- Authors: Badat, Saleem
- Date: 2012
- Language: English
- Type: text
- Identifier: vital:7584 , http://hdl.handle.net/10962/d1006574
- Description: From introduction: Gerwel was an exceptional, courageous, gifted and pioneering South African intellectual, scholar, leader and citizen. He had a profound commitment to creating a just and humane society. Through a long and distinguished association with the higher education sector, as an academic, dean, vice-chancellor, chairperson of the Committee of University Principals in the early 1990s, chancellor, and chairperson of the Mandela Rhodes Foundation, Gerwel was an outstanding champion of higher education. As chancellor, he challenged Rhodes to become socially conscious and think critically and imaginatively about access, equity and transformation, and about its role in socioeconomic development issues in South Africa, especially in the Eastern Cape.
- Full Text:
- Date Issued: 2012
- Authors: Badat, Saleem
- Date: 2012
- Language: English
- Type: text
- Identifier: vital:7584 , http://hdl.handle.net/10962/d1006574
- Description: From introduction: Gerwel was an exceptional, courageous, gifted and pioneering South African intellectual, scholar, leader and citizen. He had a profound commitment to creating a just and humane society. Through a long and distinguished association with the higher education sector, as an academic, dean, vice-chancellor, chairperson of the Committee of University Principals in the early 1990s, chancellor, and chairperson of the Mandela Rhodes Foundation, Gerwel was an outstanding champion of higher education. As chancellor, he challenged Rhodes to become socially conscious and think critically and imaginatively about access, equity and transformation, and about its role in socioeconomic development issues in South Africa, especially in the Eastern Cape.
- Full Text:
- Date Issued: 2012
Remote fingerprinting and multisensor data fusion
- Hunter, Samuel O, Stalmans, Etienne, Irwin, Barry V W, Richter, John
- Authors: Hunter, Samuel O , Stalmans, Etienne , Irwin, Barry V W , Richter, John
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429813 , vital:72641 , 10.1109/ISSA.2012.6320449
- Description: Network fingerprinting is the technique by which a device or service is enumerated in order to determine the hardware, software or application characteristics of a targeted attribute. Although fingerprinting can be achieved by a variety of means, the most common technique is the extraction of characteristics from an entity and the correlation thereof against known signatures for verification. In this paper we identify multiple host-defining metrics and propose a process of unique host tracking through the use of two novel fingerprinting techniques. We then illustrate the application of host fingerprinting and tracking for increasing situational awareness of potentially malicious hosts. In order to achieve this we provide an outline of an adapted multisensor data fusion model with the goal of increasing situational awareness through observation of unsolicited network traffic.
- Full Text:
- Date Issued: 2012
- Authors: Hunter, Samuel O , Stalmans, Etienne , Irwin, Barry V W , Richter, John
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429813 , vital:72641 , 10.1109/ISSA.2012.6320449
- Description: Network fingerprinting is the technique by which a device or service is enumerated in order to determine the hardware, software or application characteristics of a targeted attribute. Although fingerprinting can be achieved by a variety of means, the most common technique is the extraction of characteristics from an entity and the correlation thereof against known signatures for verification. In this paper we identify multiple host-defining metrics and propose a process of unique host tracking through the use of two novel fingerprinting techniques. We then illustrate the application of host fingerprinting and tracking for increasing situational awareness of potentially malicious hosts. In order to achieve this we provide an outline of an adapted multisensor data fusion model with the goal of increasing situational awareness through observation of unsolicited network traffic.
- Full Text:
- Date Issued: 2012
Representations of the subject ‘woman’ and the politics of abortion: an analysis of South African newspaper articles from 1978 to 2005
- Macleod, Catriona I, Feltham-King, Tracey
- Authors: Macleod, Catriona I , Feltham-King, Tracey
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446286 , vital:74487 , xlink:href="https://doi.org/10.1080/13691058.2012.685760"
- Description: A key element in cultural and gender power relations surrounding abortion is how women who undergo an abortion are represented in public talk. We analyse how women were named and positioned, and the attendant constructions of abortion, in South African newspaper articles on abortion from 1978 to 2005, a period during which there were radical political and legislative shifts. The name ‘woman’ was the most frequently used (70% of articles) followed by ‘girl/teenager/child’ (25%), ‘mother’ (25%), ‘patient’ (11%) and ‘minor’ (6%). The subject positionings enabled by these names were dynamic and complex and were interwoven with the localised, historical politics of abortion. The ‘innocent mother’ and the bifurcated ‘patient’ (woman/foetus) positionings were invoked in earlier epochs to promote abortion under medical conditions. The ‘dangerous mother’ and woman as ‘patient’ positionings were used more frequently under liberal abortion legislation to oppose and to advocate for abortion, respectively. The positioning of the ‘girl/teenager/child’ as dependent and vulnerable was used in contradictory ways, both to oppose abortion and to argue for a liberalisation of restrictive legislation, depending on the attendant construction of abortion. The neutral naming of ‘woman’ was, at times, linked to the liberal imaginary of ‘choice’.
- Full Text:
- Date Issued: 2012
- Authors: Macleod, Catriona I , Feltham-King, Tracey
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446286 , vital:74487 , xlink:href="https://doi.org/10.1080/13691058.2012.685760"
- Description: A key element in cultural and gender power relations surrounding abortion is how women who undergo an abortion are represented in public talk. We analyse how women were named and positioned, and the attendant constructions of abortion, in South African newspaper articles on abortion from 1978 to 2005, a period during which there were radical political and legislative shifts. The name ‘woman’ was the most frequently used (70% of articles) followed by ‘girl/teenager/child’ (25%), ‘mother’ (25%), ‘patient’ (11%) and ‘minor’ (6%). The subject positionings enabled by these names were dynamic and complex and were interwoven with the localised, historical politics of abortion. The ‘innocent mother’ and the bifurcated ‘patient’ (woman/foetus) positionings were invoked in earlier epochs to promote abortion under medical conditions. The ‘dangerous mother’ and woman as ‘patient’ positionings were used more frequently under liberal abortion legislation to oppose and to advocate for abortion, respectively. The positioning of the ‘girl/teenager/child’ as dependent and vulnerable was used in contradictory ways, both to oppose abortion and to argue for a liberalisation of restrictive legislation, depending on the attendant construction of abortion. The neutral naming of ‘woman’ was, at times, linked to the liberal imaginary of ‘choice’.
- Full Text:
- Date Issued: 2012
Research Testbed Networks: Practical Tools for Service Delivery?
- Wertlen, Ronald R, Siebörger, Ingrid, Tsietsi, Mosiuoa, Shibeshi, Zelalem S, Terzoli, Alfredo
- Authors: Wertlen, Ronald R , Siebörger, Ingrid , Tsietsi, Mosiuoa , Shibeshi, Zelalem S , Terzoli, Alfredo
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429204 , vital:72567 , https://doi.org/10.1002/j.1681-4835.2012.tb00351.x
- Description: The Telkom Centre of Excellence (CoE) at Rhodes University, housed in the Computer Science department was opened in 1997. The CoE's focus on Distributed multimedia service platforms soon showed that the technology being researched could be applied in the disadvantaged peri‐urban communities. The CoE has thus concentrated its research on building a testbed network that delivers real services to real users. In 2007, the testbed was extended to include a marginalised rural area in the Siyakhula Living Lab. The greatest factor in the sustainability of the CoE testbed network has been maintaining usefulness to all the stakeholders over the last 12 years. Industrial funding, University outreach goals and research goals could all be harmonised, while sustaining the delivery of high quality informatics services in the community. This paper presents a brief case study of the communications network testbed and how it was applied to the Development Informatics space. It analyses the roles played by stakeholders in either assisting and sustaining or obstructing the service delivery. It makes key recommendations on best practices for research networks that can also bring informatics to disadvantaged communities. It shows how testbeds for the research of new technologies can be designed so as to allow Development Informatics work to take place on such networks.
- Full Text:
- Date Issued: 2012
- Authors: Wertlen, Ronald R , Siebörger, Ingrid , Tsietsi, Mosiuoa , Shibeshi, Zelalem S , Terzoli, Alfredo
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429204 , vital:72567 , https://doi.org/10.1002/j.1681-4835.2012.tb00351.x
- Description: The Telkom Centre of Excellence (CoE) at Rhodes University, housed in the Computer Science department was opened in 1997. The CoE's focus on Distributed multimedia service platforms soon showed that the technology being researched could be applied in the disadvantaged peri‐urban communities. The CoE has thus concentrated its research on building a testbed network that delivers real services to real users. In 2007, the testbed was extended to include a marginalised rural area in the Siyakhula Living Lab. The greatest factor in the sustainability of the CoE testbed network has been maintaining usefulness to all the stakeholders over the last 12 years. Industrial funding, University outreach goals and research goals could all be harmonised, while sustaining the delivery of high quality informatics services in the community. This paper presents a brief case study of the communications network testbed and how it was applied to the Development Informatics space. It analyses the roles played by stakeholders in either assisting and sustaining or obstructing the service delivery. It makes key recommendations on best practices for research networks that can also bring informatics to disadvantaged communities. It shows how testbeds for the research of new technologies can be designed so as to allow Development Informatics work to take place on such networks.
- Full Text:
- Date Issued: 2012
Reverse saturation absorption spectra and optical limiting properties of chlorinated tetrasubstituted phthalocyanines containing different metals
- Tuhl, Ahmad, Manaa, Hacene, Makhseed, Saad, Al-Awadi, Nouria, Matthew, Jacob, Ibrahim, Hamada Mohamed, Nyokong, Tebello, Behbehani, Haider
- Authors: Tuhl, Ahmad , Manaa, Hacene , Makhseed, Saad , Al-Awadi, Nouria , Matthew, Jacob , Ibrahim, Hamada Mohamed , Nyokong, Tebello , Behbehani, Haider
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243498 , vital:51158 , xlink:href="https://doi.org/10.1016/j.optmat.2012.05.018"
- Description: A highly non-aggregated series of peripherally tetra(2,6-diisopropylphenoxy) substituted phthalocyanines (Pcs) containing different metals (Al, Ga, In and Zn) were prepared and their nonlinear optical properties (NLO), including the optical limiting behavior were investigated. This study explores the effect of the implanted metals along with the peripheral chlorine atoms on the NLO of the prepared complexes, thereby improving their optical limiting performance. The best wavelength at which the Pc complex exhibits the strongest nonlinear effect was determined over the low absorption window region (420–590 nm) comprised between the Q and B bands using a nanosecond pulsed laser with the aid of a Z-scan technique. The excited state absorption cross sections (σeff) have been found to be wavelength dependent with common double peaks at 505 nm and around 485 nm and the highest value was calculated for Pc1–In (1.1 × 10−16 cm2). The figure of merit spectra show different spectral structure when compared to the excited state absorption spectra and the largest figure of merit value was found to be around 107 for Pc1–In derivative. In full agreement with reverse saturation results, the optical limiting measurements, carried out at 485 nm and 532 nm for each derivative, show very low optical limiting thresholds at the former wavelength. In the continuous wave excitation regime, the Z-scan measurements, which were carried out at 632.8 and 532 nm, showed strong refractive and absorptive nonlinear effects.
- Full Text:
- Date Issued: 2012
- Authors: Tuhl, Ahmad , Manaa, Hacene , Makhseed, Saad , Al-Awadi, Nouria , Matthew, Jacob , Ibrahim, Hamada Mohamed , Nyokong, Tebello , Behbehani, Haider
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243498 , vital:51158 , xlink:href="https://doi.org/10.1016/j.optmat.2012.05.018"
- Description: A highly non-aggregated series of peripherally tetra(2,6-diisopropylphenoxy) substituted phthalocyanines (Pcs) containing different metals (Al, Ga, In and Zn) were prepared and their nonlinear optical properties (NLO), including the optical limiting behavior were investigated. This study explores the effect of the implanted metals along with the peripheral chlorine atoms on the NLO of the prepared complexes, thereby improving their optical limiting performance. The best wavelength at which the Pc complex exhibits the strongest nonlinear effect was determined over the low absorption window region (420–590 nm) comprised between the Q and B bands using a nanosecond pulsed laser with the aid of a Z-scan technique. The excited state absorption cross sections (σeff) have been found to be wavelength dependent with common double peaks at 505 nm and around 485 nm and the highest value was calculated for Pc1–In (1.1 × 10−16 cm2). The figure of merit spectra show different spectral structure when compared to the excited state absorption spectra and the largest figure of merit value was found to be around 107 for Pc1–In derivative. In full agreement with reverse saturation results, the optical limiting measurements, carried out at 485 nm and 532 nm for each derivative, show very low optical limiting thresholds at the former wavelength. In the continuous wave excitation regime, the Z-scan measurements, which were carried out at 632.8 and 532 nm, showed strong refractive and absorptive nonlinear effects.
- Full Text:
- Date Issued: 2012
Rhodes University 2012 Graduation Ceremonies Address
- Authors: Badat, Saleem
- Date: 2012
- Language: English
- Type: text
- Identifier: vital:7588 , http://hdl.handle.net/10962/d1006579
- Description: From introduction: We take pride in our striving to ensure that we are an environment in which knowledge, understanding and the intellect can flower; in being a leading postgraduate and research university that takes undergraduate studies seriously; in enjoying among the best pass and graduation rates in South Africa; in our increasing engagement with local communities; in the pursuit of equity and excellence, and in being a cosmopolitan institution with students from some 56 countries.
- Full Text:
- Date Issued: 2012
- Authors: Badat, Saleem
- Date: 2012
- Language: English
- Type: text
- Identifier: vital:7588 , http://hdl.handle.net/10962/d1006579
- Description: From introduction: We take pride in our striving to ensure that we are an environment in which knowledge, understanding and the intellect can flower; in being a leading postgraduate and research university that takes undergraduate studies seriously; in enjoying among the best pass and graduation rates in South Africa; in our increasing engagement with local communities; in the pursuit of equity and excellence, and in being a cosmopolitan institution with students from some 56 countries.
- Full Text:
- Date Issued: 2012
Rhodes University Graduation Ceremony 2012
- Authors: Rhodes University
- Date: 2012
- Language: English
- Type: text
- Identifier: vital:8135 , http://hdl.handle.net/10962/d1007245
- Description: Rhodes University Graduation Ceremonies 2012 [at] 1820 Settlers National Monument Thursday, 12 April at 18.00 [and] Friday, 13 April at 10:30; 14:30 & 18:00 [and] Saturday, 14 April at 10:30 , Rhodes University Awards, Scholarships, Bursaries and Prizes 2012
- Full Text:
- Date Issued: 2012
- Authors: Rhodes University
- Date: 2012
- Language: English
- Type: text
- Identifier: vital:8135 , http://hdl.handle.net/10962/d1007245
- Description: Rhodes University Graduation Ceremonies 2012 [at] 1820 Settlers National Monument Thursday, 12 April at 18.00 [and] Friday, 13 April at 10:30; 14:30 & 18:00 [and] Saturday, 14 April at 10:30 , Rhodes University Awards, Scholarships, Bursaries and Prizes 2012
- Full Text:
- Date Issued: 2012
Richard T. Carson: Contingent valuation: a comprehensive bibliography and history
- Authors: Snowball, Jeanette D
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71504 , vital:29859 , https://link.springer.com/content/pdf/10.1007/s10824-012-9165-7.pdf
- Description: For those of us who have been involved in willingness to pay studies for some time, Contingent Valuation: A comprehensive bibliography and history by Richard Carson is a fascinating read, tracking the early development of the method and debates around it from an insider’s perspective. As someone who has not only been involved in contingent valuation research over many years, but who has also been instrumental in shaping it, Richard Carson is the ideal author of this carefully crafted book.
- Full Text:
- Date Issued: 2012
- Authors: Snowball, Jeanette D
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71504 , vital:29859 , https://link.springer.com/content/pdf/10.1007/s10824-012-9165-7.pdf
- Description: For those of us who have been involved in willingness to pay studies for some time, Contingent Valuation: A comprehensive bibliography and history by Richard Carson is a fascinating read, tracking the early development of the method and debates around it from an insider’s perspective. As someone who has not only been involved in contingent valuation research over many years, but who has also been instrumental in shaping it, Richard Carson is the ideal author of this carefully crafted book.
- Full Text:
- Date Issued: 2012
Ritualised discourse practices of feedback in a university foundation programme: a critical investigation
- Authors: Richardson, Amy
- Date: 2012
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MA
- Identifier: http://hdl.handle.net/10962/164955 , vital:41187
- Description: In order for students to become true members of academic communities of practice they need epistemological access, including guidance on central institutional knowledge-producing processes and mastery of key academic literacy practices. A powerful source of guidance is marker feedback. Drawing on key insights from the New Literacy Studies and taking up the mandate of Critical Ethnography to improve the status quo, this thesis reports on the feedback practices in a university foundation programme. The findings are based on three micro-case studies compiled and analysed by means of methods drawn from Ethnography, Sociolinguistics and Critical Analysis in conjunction with an expanded, multimodal, APPRAISAL analysis, including adjusted categories and the author’s own feedback typologies. Two major arguments emerge: the feedback provided amounts to a set of ritualised discourse practices and its effects can be likened to the product of the children’s game of Head-body-tail. Consequently, feedback conventions are opaque and, potentially, impede epistemological access. They further entrench five sets of ideologies: (1) Students must master basic English literacy before they are coached in more complex issues such as argumentation; an assumption which leads to differential socialisation. (2) There is a single set of literacy practices that is rewarded. (3) Students have different levels of authorial authority depending on their language abilities. (4) ‘Middle students’ may benefit the most from feedback. (5) Specific comments are preferred over general ones. Analysis of feedback, furthermore, shows that markers’ frames of reference shape their pedagogy and that draft and final versions of work may be framed differently by markers. These findings require a response and, in order to facilitate epistemological access, suggestions are made for improved marker training based on the problematisation of the ritual involved in marking students’ work in this university foundation programme. , Thesis (MA)--Rhodes University, Faculty of Humanities, Linguistics, 2012
- Full Text:
- Date Issued: 2012
- Authors: Richardson, Amy
- Date: 2012
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MA
- Identifier: http://hdl.handle.net/10962/164955 , vital:41187
- Description: In order for students to become true members of academic communities of practice they need epistemological access, including guidance on central institutional knowledge-producing processes and mastery of key academic literacy practices. A powerful source of guidance is marker feedback. Drawing on key insights from the New Literacy Studies and taking up the mandate of Critical Ethnography to improve the status quo, this thesis reports on the feedback practices in a university foundation programme. The findings are based on three micro-case studies compiled and analysed by means of methods drawn from Ethnography, Sociolinguistics and Critical Analysis in conjunction with an expanded, multimodal, APPRAISAL analysis, including adjusted categories and the author’s own feedback typologies. Two major arguments emerge: the feedback provided amounts to a set of ritualised discourse practices and its effects can be likened to the product of the children’s game of Head-body-tail. Consequently, feedback conventions are opaque and, potentially, impede epistemological access. They further entrench five sets of ideologies: (1) Students must master basic English literacy before they are coached in more complex issues such as argumentation; an assumption which leads to differential socialisation. (2) There is a single set of literacy practices that is rewarded. (3) Students have different levels of authorial authority depending on their language abilities. (4) ‘Middle students’ may benefit the most from feedback. (5) Specific comments are preferred over general ones. Analysis of feedback, furthermore, shows that markers’ frames of reference shape their pedagogy and that draft and final versions of work may be framed differently by markers. These findings require a response and, in order to facilitate epistemological access, suggestions are made for improved marker training based on the problematisation of the ritual involved in marking students’ work in this university foundation programme. , Thesis (MA)--Rhodes University, Faculty of Humanities, Linguistics, 2012
- Full Text:
- Date Issued: 2012
Schottky barrier diode parameters of Ag/MgPc/p-Si structure
- Canlıca, Mevlüde, Coskun, Mustafa, Altındal, Ahmet, Nyokong, Tebello
- Authors: Canlıca, Mevlüde , Coskun, Mustafa , Altındal, Ahmet , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/245820 , vital:51408 , xlink:href="https://doi.org/10.1142/S1088424612500824"
- Description: An Ag/Pc/p-Si Schottky barrier (SB) diode was fabricated. The current-voltage (I-V), capacitance-voltage (C-V) and conductance-voltage (G-V) measurements were carried out to determine the characteristic parameters such as barrier height, ideality factor and series resistance of the SB diode. The non-linear behavior of ln (I) vs. ln (V) and ln (I/V) vs. V1/2 plots indicated that the thermoionic emission theory can be applied to evaluate junction parameters for the investigated SB diode rather than space-charge limited conduction (SCLC) mechanism and bulk-limited Poole–Frenkel emission. The bulk doping concentration NB and fixed oxide charges Nf was determined from the measured high frequency C-V curve and was found to be 9.5 × 1014 cm-3 and 2.3 × 1013 cm-2, respectively. The values of barrier height obtained from Norde's function were compared with those from the forward bias current-voltage characteristic, and it was seen that there was a good agreement between barrier heights from both methods.
- Full Text:
- Date Issued: 2012
- Authors: Canlıca, Mevlüde , Coskun, Mustafa , Altındal, Ahmet , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/245820 , vital:51408 , xlink:href="https://doi.org/10.1142/S1088424612500824"
- Description: An Ag/Pc/p-Si Schottky barrier (SB) diode was fabricated. The current-voltage (I-V), capacitance-voltage (C-V) and conductance-voltage (G-V) measurements were carried out to determine the characteristic parameters such as barrier height, ideality factor and series resistance of the SB diode. The non-linear behavior of ln (I) vs. ln (V) and ln (I/V) vs. V1/2 plots indicated that the thermoionic emission theory can be applied to evaluate junction parameters for the investigated SB diode rather than space-charge limited conduction (SCLC) mechanism and bulk-limited Poole–Frenkel emission. The bulk doping concentration NB and fixed oxide charges Nf was determined from the measured high frequency C-V curve and was found to be 9.5 × 1014 cm-3 and 2.3 × 1013 cm-2, respectively. The values of barrier height obtained from Norde's function were compared with those from the forward bias current-voltage characteristic, and it was seen that there was a good agreement between barrier heights from both methods.
- Full Text:
- Date Issued: 2012
Seasonal distribution, breeding season and wing moult in the Splendid Glossy Starling Lamprotornis splendidus
- Authors: Craig, Adrian J F K
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449535 , vital:74828 , https://doi.org/10.2989/00306525.2012.655429
- Description: Seasonal migration by Splendid Glossy Starlings has been confirmed only for Kenya and Zambia. Populations in almost all other countries have been categorised as ‘resident’ by some observers, but ‘nomadic’ is a more accurate description of their status. The breeding season is accurately known for few localities. Estimates for the duration of wing moult ranged from 70–130 d based on small samples. Regional divergences in the timing of wing moult remain open to three possible interpretations: (1) differences between years in the timing of wing moult; (2) differences between sex and/or age classes; and (3) population movements, so that birds from different regions may successively occupy the same areas. The available data are inadequate to resolve these questions.
- Full Text:
- Date Issued: 2012
- Authors: Craig, Adrian J F K
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449535 , vital:74828 , https://doi.org/10.2989/00306525.2012.655429
- Description: Seasonal migration by Splendid Glossy Starlings has been confirmed only for Kenya and Zambia. Populations in almost all other countries have been categorised as ‘resident’ by some observers, but ‘nomadic’ is a more accurate description of their status. The breeding season is accurately known for few localities. Estimates for the duration of wing moult ranged from 70–130 d based on small samples. Regional divergences in the timing of wing moult remain open to three possible interpretations: (1) differences between years in the timing of wing moult; (2) differences between sex and/or age classes; and (3) population movements, so that birds from different regions may successively occupy the same areas. The available data are inadequate to resolve these questions.
- Full Text:
- Date Issued: 2012
Service discovery using open sound control
- Eales, Andrew, Foss, Richard
- Authors: Eales, Andrew , Foss, Richard
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426890 , vital:72398 , https://www.aes.org/e-lib/online/browse.cfm?elib=16432
- Description: The Open Sound Control (OSC) control protocol does not have service discovery capabilities. The approach to adding service discovery to OSC proposed in this paper uses the OSC address space to represent services within the context of a logical device model. This model allows services to be represented in a context-sensitive manner by relating parameters representing services to the logical organization of a device. Implementation of service discovery is done using standard OSC messages and requires that the OSC address space be designed to support these messages. This paper illustrates how these enhancements to OSC allow a device to advertise its services. Controller applications can then explore the device’s address space to discover services and retrieve the services required by the application. The Open Sound Control (OSC) control protocol does not have service discovery capabilities. The approach to adding service discovery to OSC proposed in this paper uses the OSC address space to represent services within the context of a logical device model. This model allows services to be represented in a context-sensitive manner by relating parameters representing services to the logical organization of a device. Implementation of service discovery is done using standard OSC messages and requires that the OSC address space be designed to support these messages. This paper illustrates how these enhancements to OSC allow a device to advertise its services. Controller applications can then explore the device’s address space to discover services and retrieve the services required by the application.
- Full Text:
- Date Issued: 2012
- Authors: Eales, Andrew , Foss, Richard
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426890 , vital:72398 , https://www.aes.org/e-lib/online/browse.cfm?elib=16432
- Description: The Open Sound Control (OSC) control protocol does not have service discovery capabilities. The approach to adding service discovery to OSC proposed in this paper uses the OSC address space to represent services within the context of a logical device model. This model allows services to be represented in a context-sensitive manner by relating parameters representing services to the logical organization of a device. Implementation of service discovery is done using standard OSC messages and requires that the OSC address space be designed to support these messages. This paper illustrates how these enhancements to OSC allow a device to advertise its services. Controller applications can then explore the device’s address space to discover services and retrieve the services required by the application. The Open Sound Control (OSC) control protocol does not have service discovery capabilities. The approach to adding service discovery to OSC proposed in this paper uses the OSC address space to represent services within the context of a logical device model. This model allows services to be represented in a context-sensitive manner by relating parameters representing services to the logical organization of a device. Implementation of service discovery is done using standard OSC messages and requires that the OSC address space be designed to support these messages. This paper illustrates how these enhancements to OSC allow a device to advertise its services. Controller applications can then explore the device’s address space to discover services and retrieve the services required by the application.
- Full Text:
- Date Issued: 2012
Sex work: discussion document 27-29 March 2012
- Congress of South African Trade Unions (COSATU)
- Authors: Congress of South African Trade Unions (COSATU)
- Date: 2012
- Subjects: Uncatalogued
- Language: English
- Type: book , text
- Identifier: http://hdl.handle.net/10962/68748 , vital:29311
- Description: The aim of this paper is to resuscitate the debate on the need for decriminalization of sex work and ensure that COSATU and its affiliates further engage within structures, alliance, non -governmental organizations and with the Government in terms of the need for law reform and identify alternative policy framework. However, whatever outcome of the legal processes pertaining to sex work, should be abide by the spirit of the Constitution which is committed to advancing human rights and social justice. Sex work in South Africa is currently criminalised and is restricted by the Sexual Offences Act of 1957 (an un-amended apartheid-era law) which prohibits all activities associated with it. The criminal offences related to sex work include amongst them the keeping or participating in the management of a brothel, procuring someone to become a sex worker, soliciting or selling sex or living of the earnings of a sex worker. In 2007 through the Sexual Offences Act their clients were also criminalised In 2007, the Act was amended to criminalise buyers of sexual services too (SALRC 2009). We therefore argue that the existing laws on sex work are nothing but hypocrisy of the conservatives and elites. They do not improve the conditions of women; instead they worsen the miserable conditions that women in the sex trade already find themselves in. The missing fact is that sex work is a by-product of our patriarchal capitalist society-not something created by some “immoral prostitute” The current oppressive legislation on sex work has stimulated a lot of debates and has led to an upsurge in advocacy work by individuals and organizations around the need to either legalise or decriminalize sex work. Likewise, Cosatu as a key civil society player has also played a leading role in its endeavor to unite the working class and to defend workers from exploitation as well as finding workable solutions to the plight of the most vulnerable people in our society who find themselves with no choice but to engage in sex work. The sex industry is by nature exploitative and inherently dangerous. Women in the industry experience different degrees of abuse, coercion and violence, but all of them are harmed physically and psychologically. As a trade union movement, COSATU has an interest in the debate about sex work, from the point of view that sex work targets mainly the working class and the poor, predominantly black women. High levels of unemployment, poverty and gender inequality are key factors driving sex work. The global economic crisis has aggravated the situation for the poor majority through job losses, casualisation and ultimately increased feminization of poverty. Cosatu has already started some debates and campaigns aimed at devising ways of protecting sex workers through collective workers struggles. As such, the sex work discourse and campaign among Cosatu affiliates for decriminalization was tabled at the Federation’s 10th Congress though it was deferred because of contestation and opposition amongst delegates. However, affiliates had the responsibility to go back and make further consultations, sensitization with their structures and open up a discussion at the level of the COSATU Central Executive Committee. Indeed, it is high time that the debate on decriminalization should be concluded and that sex work be recognized as work as Arnott and Crago (2009) argue that: “The criminalisation of sex work has precluded the enforcement and protection of sex workers’ Labour rights. This disregard for sex workers as workers has left many of those employed in brothels in South Africa vulnerable to labor abuses such as withheld wages, arbitrary fines, restrictions on mobility, and confiscation of belongings including medication. Sex workers on the street or working in brothels and other agencies have no recourse if customers refuse to pay them’’1 The decriminalization of sex work should take the course of a rights- based approach which means that sex workers would be able to enjoy their basic human & labour rights and be protected against sexual harassment, violence, rape and unfair working conditions. By so doing, sex workers would be able to access non-discriminatory health care services, be more empowered and operate within the ambit of protective labour and occupational health & safety laws.
- Full Text:
- Date Issued: 2012
- Authors: Congress of South African Trade Unions (COSATU)
- Date: 2012
- Subjects: Uncatalogued
- Language: English
- Type: book , text
- Identifier: http://hdl.handle.net/10962/68748 , vital:29311
- Description: The aim of this paper is to resuscitate the debate on the need for decriminalization of sex work and ensure that COSATU and its affiliates further engage within structures, alliance, non -governmental organizations and with the Government in terms of the need for law reform and identify alternative policy framework. However, whatever outcome of the legal processes pertaining to sex work, should be abide by the spirit of the Constitution which is committed to advancing human rights and social justice. Sex work in South Africa is currently criminalised and is restricted by the Sexual Offences Act of 1957 (an un-amended apartheid-era law) which prohibits all activities associated with it. The criminal offences related to sex work include amongst them the keeping or participating in the management of a brothel, procuring someone to become a sex worker, soliciting or selling sex or living of the earnings of a sex worker. In 2007 through the Sexual Offences Act their clients were also criminalised In 2007, the Act was amended to criminalise buyers of sexual services too (SALRC 2009). We therefore argue that the existing laws on sex work are nothing but hypocrisy of the conservatives and elites. They do not improve the conditions of women; instead they worsen the miserable conditions that women in the sex trade already find themselves in. The missing fact is that sex work is a by-product of our patriarchal capitalist society-not something created by some “immoral prostitute” The current oppressive legislation on sex work has stimulated a lot of debates and has led to an upsurge in advocacy work by individuals and organizations around the need to either legalise or decriminalize sex work. Likewise, Cosatu as a key civil society player has also played a leading role in its endeavor to unite the working class and to defend workers from exploitation as well as finding workable solutions to the plight of the most vulnerable people in our society who find themselves with no choice but to engage in sex work. The sex industry is by nature exploitative and inherently dangerous. Women in the industry experience different degrees of abuse, coercion and violence, but all of them are harmed physically and psychologically. As a trade union movement, COSATU has an interest in the debate about sex work, from the point of view that sex work targets mainly the working class and the poor, predominantly black women. High levels of unemployment, poverty and gender inequality are key factors driving sex work. The global economic crisis has aggravated the situation for the poor majority through job losses, casualisation and ultimately increased feminization of poverty. Cosatu has already started some debates and campaigns aimed at devising ways of protecting sex workers through collective workers struggles. As such, the sex work discourse and campaign among Cosatu affiliates for decriminalization was tabled at the Federation’s 10th Congress though it was deferred because of contestation and opposition amongst delegates. However, affiliates had the responsibility to go back and make further consultations, sensitization with their structures and open up a discussion at the level of the COSATU Central Executive Committee. Indeed, it is high time that the debate on decriminalization should be concluded and that sex work be recognized as work as Arnott and Crago (2009) argue that: “The criminalisation of sex work has precluded the enforcement and protection of sex workers’ Labour rights. This disregard for sex workers as workers has left many of those employed in brothels in South Africa vulnerable to labor abuses such as withheld wages, arbitrary fines, restrictions on mobility, and confiscation of belongings including medication. Sex workers on the street or working in brothels and other agencies have no recourse if customers refuse to pay them’’1 The decriminalization of sex work should take the course of a rights- based approach which means that sex workers would be able to enjoy their basic human & labour rights and be protected against sexual harassment, violence, rape and unfair working conditions. By so doing, sex workers would be able to access non-discriminatory health care services, be more empowered and operate within the ambit of protective labour and occupational health & safety laws.
- Full Text:
- Date Issued: 2012
Single walled carbon nanotubes functionalized with nickel phthalocyanines
- Khene, Samson, Nyokong, Tebello
- Authors: Khene, Samson , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/245843 , vital:51410 , xlink:href="https://doi.org/10.1142/S1088424611004439"
- Description: In this work we report on electrochemical behavior of nickel phthalocyanine derivatives tetrasubstituted peripherally and non-peripherally with hydroxy and used to modify single walled carbon nanotubes. Nickel phthalocyanine complex octasubstituted at the peripheral positions with hydroxy groups was also used to modify single walled carbon nanotubes. Nickel phthalocyanine complex tetrasubstituted with amino groups at peripheral position was covalently and non-covalently linked to single walled carbon nanotubes. All the conjugates of nickel phthalocyanine derivatives with single walled carbon nanotubes were used for the electro oxidation of 4-chlorophenol. The nickel phthalocyanine octabsubstituted with hydroxy groups at the non-peripheral positions gave the best current response and the best resistance against electrode fouling for the oxidation of 4-chlorophenol.
- Full Text:
- Date Issued: 2012
- Authors: Khene, Samson , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/245843 , vital:51410 , xlink:href="https://doi.org/10.1142/S1088424611004439"
- Description: In this work we report on electrochemical behavior of nickel phthalocyanine derivatives tetrasubstituted peripherally and non-peripherally with hydroxy and used to modify single walled carbon nanotubes. Nickel phthalocyanine complex octasubstituted at the peripheral positions with hydroxy groups was also used to modify single walled carbon nanotubes. Nickel phthalocyanine complex tetrasubstituted with amino groups at peripheral position was covalently and non-covalently linked to single walled carbon nanotubes. All the conjugates of nickel phthalocyanine derivatives with single walled carbon nanotubes were used for the electro oxidation of 4-chlorophenol. The nickel phthalocyanine octabsubstituted with hydroxy groups at the non-peripheral positions gave the best current response and the best resistance against electrode fouling for the oxidation of 4-chlorophenol.
- Full Text:
- Date Issued: 2012
Social recruiting: a next generation social engineering attack
- Schoeman, A H B, Irwin, Barry V W
- Authors: Schoeman, A H B , Irwin, Barry V W
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428600 , vital:72523 , https://www.jstor.org/stable/26486876
- Description: Social engineering attacks initially experienced success due to the lack of understanding of the attack vector and resultant lack of remedial actions. Due to an increase in media coverage corporate bodies have begun to defend their interests from this vector. This has resulted in a new generation of social engineering attacks that have adapted to the industry response. These new forms of attack take into account the increased likelihood that they will be detected; rendering traditional defences against social engineering attacks moot. This paper highlights these attacks and will explain why traditional defences fail to address them as well as suggest new methods of incident response.
- Full Text:
- Date Issued: 2012
- Authors: Schoeman, A H B , Irwin, Barry V W
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428600 , vital:72523 , https://www.jstor.org/stable/26486876
- Description: Social engineering attacks initially experienced success due to the lack of understanding of the attack vector and resultant lack of remedial actions. Due to an increase in media coverage corporate bodies have begun to defend their interests from this vector. This has resulted in a new generation of social engineering attacks that have adapted to the industry response. These new forms of attack take into account the increased likelihood that they will be detected; rendering traditional defences against social engineering attacks moot. This paper highlights these attacks and will explain why traditional defences fail to address them as well as suggest new methods of incident response.
- Full Text:
- Date Issued: 2012
Spectral, photophysical and photochemical properties of tetra-and octaglycosylated zinc phthalocyanines
- Iqbal, Zafar, Masilela, Nkosiphile, Nyokong, Tebello, Lyubimtsev, Alexey, Hanack, Michael, Ziegler, Thomas
- Authors: Iqbal, Zafar , Masilela, Nkosiphile , Nyokong, Tebello , Lyubimtsev, Alexey , Hanack, Michael , Ziegler, Thomas
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244428 , vital:51256 , xlink:href="https://doi.org/10.1039/c2pp05348a"
- Description: Photophysical and photochemical properties of a series of tetra- and octaglycosylated zinc phthalocyanines (ZnPcs) substituted with glucose and galactose moieties have been reported. Spectral properties of these phthalocyanines are compared in DMSO. Absorption spectra of the non-peripherally tetra-substituted ZnPcs 2 showed a significant red shift in their Q-band maxima as compared to the peripherally substituted analog 1. All the complexes gave high triplet quantum yields ranging from 0.68 to 0.88, whereas triplet lifetimes were in the range of 100–430 µs in argon-saturated solutions. The octagalactosylated ZnPc 3b showed the highest triplet quantum yield and singlet oxygen quantum yield of 0.88 and 0.69, respectively. The fluorescence quantum yields and lifetimes of all the compounds under investigation were within the range of zinc phthalocyanine complexes.
- Full Text:
- Date Issued: 2012
- Authors: Iqbal, Zafar , Masilela, Nkosiphile , Nyokong, Tebello , Lyubimtsev, Alexey , Hanack, Michael , Ziegler, Thomas
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244428 , vital:51256 , xlink:href="https://doi.org/10.1039/c2pp05348a"
- Description: Photophysical and photochemical properties of a series of tetra- and octaglycosylated zinc phthalocyanines (ZnPcs) substituted with glucose and galactose moieties have been reported. Spectral properties of these phthalocyanines are compared in DMSO. Absorption spectra of the non-peripherally tetra-substituted ZnPcs 2 showed a significant red shift in their Q-band maxima as compared to the peripherally substituted analog 1. All the complexes gave high triplet quantum yields ranging from 0.68 to 0.88, whereas triplet lifetimes were in the range of 100–430 µs in argon-saturated solutions. The octagalactosylated ZnPc 3b showed the highest triplet quantum yield and singlet oxygen quantum yield of 0.88 and 0.69, respectively. The fluorescence quantum yields and lifetimes of all the compounds under investigation were within the range of zinc phthalocyanine complexes.
- Full Text:
- Date Issued: 2012
Spectroscopic and physicochemical behavior of magnesium phthalocyanine derivatives mono-substituted with a carboxylic acid group
- Nombona, Nolwazi, Chidawanyika, Wadzanai J U, Nyokong, Tebello
- Authors: Nombona, Nolwazi , Chidawanyika, Wadzanai J U , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244450 , vital:51258 , xlink:href="https://doi.org/10.1016/j.molstruc.2011.12.051"
- Description: This work reports on the synthesis of novel unsymmetrically substituted magnesium phthalocyanine complexes containing one carboxyl group. The physicochemical behavior of these complexes were compared with those of their unmetallated and zinc counterparts. The MgPcs showed interesting absorption spectra with [8,15,22-Tris-(naphtho)-4,5-(3-carboxy-1,2-dioxyphenyl)phthalocyaninato]magnesium (II) showing a large split in the Q band whereas [8,15,22-Tris-(naphtho)-2-(carboxy) phthalocyaninato]magnesium(II) presented only a small splitting. The magnesium phthalocyanine derivatives displayed higher fluorescence quantum yields compared to unmetallated and zinc phthalocyanine counterparts. The latter gave admirable triplet and singlet oxygen quantum yields. These molecules can distinctly be employed in the field of photodynamic therapy in combination with fluorescence imaging.
- Full Text:
- Date Issued: 2012
- Authors: Nombona, Nolwazi , Chidawanyika, Wadzanai J U , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244450 , vital:51258 , xlink:href="https://doi.org/10.1016/j.molstruc.2011.12.051"
- Description: This work reports on the synthesis of novel unsymmetrically substituted magnesium phthalocyanine complexes containing one carboxyl group. The physicochemical behavior of these complexes were compared with those of their unmetallated and zinc counterparts. The MgPcs showed interesting absorption spectra with [8,15,22-Tris-(naphtho)-4,5-(3-carboxy-1,2-dioxyphenyl)phthalocyaninato]magnesium (II) showing a large split in the Q band whereas [8,15,22-Tris-(naphtho)-2-(carboxy) phthalocyaninato]magnesium(II) presented only a small splitting. The magnesium phthalocyanine derivatives displayed higher fluorescence quantum yields compared to unmetallated and zinc phthalocyanine counterparts. The latter gave admirable triplet and singlet oxygen quantum yields. These molecules can distinctly be employed in the field of photodynamic therapy in combination with fluorescence imaging.
- Full Text:
- Date Issued: 2012