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Photodynamic therapy activity of zinc phthalocyanine linked to folic acid and magnetic nanoparticles

- Matlou, Gauta G, Oluwole, David O, Prinsloo, Earl, Nyokong, Tebello

Authors: Matlou, Gauta G , Oluwole, David O , Prinsloo, Earl , Nyokong, Tebello
Date: 2018
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/234429 , vital:50195 , xlink:href="https://doi.org/10.1016/j.jphotobiol.2018.07.025"
Description: In this work, the photodynamic therapy (PDT) activities (using human carcinoma adherent MCF-7 cells) of zinc phthalocyanine derivatives: complexes 1 (Zn mono cinnamic acid phthalocyanine) and 2 (zinc mono carboxyphenoxy phthalocyanine) when covalently linked to folic acid (FA) and amine functionalized magnetic nanoparticles (AMNPs) are reported. The covalent linkage of asymmetric zinc cinnamic acid Pc (1) to FA (1-FA) through an amide bond is reported for the first time. Complex 1 is insoluble in water, but upon linkage to FA, (to form 1-FA) the molecule become water soluble, hence the UV–Vis spectrum and singlet oxygen quantum yield for 1-FA were also done in water since water solubility is essential for biological applications. The reported 2-FA is also water soluble. Linking complexes 1 and 2 to FA and AMNPs decreased the dark toxicity of 1 and 2 on MCF-7 cells. Pc-FA (1-FA and 2-FA) conjugates had better singlet oxygen quantum yields (Φ∆) in DMSO as compared to Pc-AMNPs (1-AMNPs and 2-AMNPs). The water- soluble 1-FA and 2-FA also achieved a better photodynamic therapy (PDT) activity as compared to 1-AMNPs and 2-AMNPs. Folic acid targeting on the tumor cells may have also facilitated better bioavailability of 1-FA and 2-FA and improved PDT activity on MCF-7 cells over AMNPs carriers.
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Date Issued: 2018

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Being moved by a way the world is not

- Jones, Ward E

Authors: Jones, Ward E
Date: 2011
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/275631 , vital:55064 , xlink:href="https://doi.org/10.1007/s11229-009-9522-z"
Description: At the end of Lecture 3 of The Empirical Stance, Bas van Fraassen suggests that we see the change of view involved in scientific revolutions as being, at least in part, emotional. In this paper, I explore one plausible way of cashing out this suggestion. Someone’s emotional approval of a description of the world, I argue, thereby shows that she takes herself to have reason to take that description seriously. This is true even if she is convinced—as a scientific community is when it considers alternative theories—that this description is false, that it is not the way the world is.
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Date Issued: 2011

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(Ferrocenylpyrazolyl) zinc (II) benzoates as catalysts for the ring opening polymerization of ε-caprolactone

- Obuah, Collins, Lochee, Yemanlall, Jordaan, Johan H L, Otto, Daniel P, Nyokong, Tebello, Darkwa, James

Authors: Obuah, Collins , Lochee, Yemanlall , Jordaan, Johan H L , Otto, Daniel P , Nyokong, Tebello , Darkwa, James
Date: 2015
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/189515 , vital:44853 , xlink:href="https://doi.org/10.1016/j.poly.2015.02.007"
Description: The reaction of Zn(OAc)2 and C6H5COOH or 3,5-NO2-C6H3COOH with 3-ferrocenylpyrazolyl-methylenepyridine (L1), 3-ferrocenyl-5-methylpyrazolyl-methylenepyridine (L2), 3-ferrocenylpyrazolyl-ethylamine (L3) and 3-ferrocenyl-5-pyrazolyl-ethylamine (L4) afford the corresponding complexes [Zn(C6H5COO)2(L1)] (1), [Zn(C6H5COO)2(L2)] (2), [Zn(3,5-NO2-C6H3COO)2(L1)] (3), [Zn(3,5-NO2-C6H3 COO)2(L2)] (4), [Zn(C6H5COO)2(L3)] (5), [Zn(C6H5COO)2(L4)] (6), [Zn(3,5-NO2-C6H3COO)2(L3)] (7) and [Zn(3,5-NO2-C6H3COO)2(L4)] (8). These complexes behave as catalysts for the ring opening polymerization of e-caprolactone to produce polymers with molecular weight that range from 1480 to 7080 g mol1 and exhibited moderate to broad PDIs. Evidence of these complexes acting as catalysts was obtained from both the polymerization data and kinetic studies. The polymerization data show that variation of the [CL]/[C] from 100 to 800 produced PCL with relatively the same molecular weight indicative of a catalyst behavior. The appearance of induction period in kinetic plots strengthens the fact that these complexes are catalysts rather than initiators. MALDI-TOF MS and 1 H NMR data show di-hydroxy end groups, which support the coordination mechanism rather than insertion mechanism. To understand the broad PDIs obtained for some of the polymer, the electronic properties of the zinc complexes were investigated using cyclic voltammetry. The results show that the zinc complexes containing amine based ligands are highly electrophilic therefore making them unstable, hence the broad PDIs observed for zinc complexes containing amine based ligands. Among the eight complexes investigated, complex 7 is the most active catalyst with kp value of 1.18 107 h1 mol1 at 110 C.
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Date Issued: 2015

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Electrocatalytic oxidation of cysteine by molybdenum (V) phthalocyanine complexes

- Mafatle, Tsukutlane J, Nyokong, Tebello

Authors: Mafatle, Tsukutlane J , Nyokong, Tebello
Date: 1996
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/293369 , vital:57079 , xlink:href="https://doi.org/10.1016/0022-0728(95)04519-8"
Description: Chemically modified electrodes, constructed by incorporating oxomolybdenum(V) phthalocyanine (OMo(V)(OH)Pc, Pc = phthalocyanine dianion) into graphite powder were used to catalyse the oxidation of cysteine. Solution catalysis of cysteine by oxomolybdenum(V) tetrasulfophthalocyanine, [OMo(V)(OH)TSPc]4−, was also investigated. A considerable reduction in overpotential for cysteine oxidation was observed. Cysteine oxidation occurred at 0.26 and 0.28 V vs. Ag/vbAgCl for catalysis by Omo(V)(OH)Pc and [OMo(V)(OH)TSPc]4− respectively as opposed to 0.77 V vs. Ag/vbAgCl observed on CoPc chemically modified electrodes. The anodic peak currents vary linearly with cysteine concentration in the range 0.02 to 0.08 mol dm−3 and 0.008 to 0.02 mol dm−3 for [OMo(V)(OH)TSPc]4− and OMo(V)Pc respectively.
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Date Issued: 1996

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Effect of doping vs covalent linking of a low symmetry zinc phthalocyanine to silica nanoparticles on singlet oxygen production

- Peteni, Siwaphiwe, Nyokong, Tebello

Authors: Peteni, Siwaphiwe , Nyokong, Tebello
Date: 2018
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/187873 , vital:44705 , xlink:href="https://doi.org/10.1016/j.ica.2018.06.029"
Description: Tris[(4-(pyridin-4-ylthio)-2-thio-4-methylthiazol-5-yl)acetic acid phthalocyaninato] zinc (II) (3) was covalently linked to and doped onto SiNPs. An increase in triplet quantum yields for 3-SiNPs (linked) with decreasing lifetimes was observed. For 3-SiNPs (doped) there was a decrease in both the triplet quantum yield and lifetimes when compared to 3 alone. There was an increase in singlet oxygen quantum yields for 3-SiNPs (linked) compared to 3 from 0.67 to 0.80, while there was a decrease for 3-SiNPs (doped) to 0.25.
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Date Issued: 2018

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White anti-racism in post-apartheid South Africa:

- Matthews, Sally

Authors: Matthews, Sally
Date: 2012
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/142361 , vital:38073 , DOI: 10.1080/02589346.2012.683938
Description: South Africans today live not only with the memory of the racial injustices of the past, but also with present injustices that are a consequence of that past. How should white South Africans live with these past and present injustices? On recognition of the racial injustices of the past and of the continuation of forms of white privilege today, involvement in ongoing anti-racist struggles seems to be an appropriate way for white South Africans to respond to past and present injustices. However, some discussions of the way in which white privilege operates and is perpetuated in post-segregationist societies suggest the need for caution with regard to white involvement in anti-racist struggles, arguing that some of the ways in which white people involve themselves in apparently anti-racist work actually result in the perpetuation rather than the erosion of white privilege. This article explores concerns about the intractability of white privilege while also ultimately defending the appropriateness of white involvement in anti-racist struggles.
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Date Issued: 2012

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Dungamanzi/stirring waters: Tsonga and Shangaan art from southern Africa, Nessa Leibhammer (Ed.): book reviews

- Simbao, Ruth K

Authors: Simbao, Ruth K
Date: 2008
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/147358 , vital:38629 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC31053
Description: A woman known as Nkoma We Lwandle (Cow of the Ocean) and a man, Dunga Manzi (Stirring Waters), are remembered as the first Tsonga diviners. Trained by Nzunzu - a powerful water serpent - they were pulled into a lake for a few months and later emerged as influential healers. Such stories (like the one relayed by Dederen of a young girl, Nsatimuni, who also temporarily disappeared into a lake) represent 'death' and 'rebirth', reflecting Arnold van Gennep's (1909) well-known schema of rites de passage: séparation, marge, and agrégation. Separated from daily life, these characters sink into another world where people breathe in water like a foetus in the liquid depths of a womb, evoking impending new birth (p. 171).
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Date Issued: 2008

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Interrogating citizen journalism practices: a case study of Rhodes University’s Lindaba Ziyafika Project

- Nyathi, Sihle, Garman, Anthea

Authors: Nyathi, Sihle , Garman, Anthea
Date: 2017
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/158915 , vital:40240 , https://doi.org/10.1080/23743670.2016.1259740
Description: Several scholars have noted that citizen journalism in the West is essentially an online phenomenon, driven by the affordability of Internet technologies. In Africa, projects such as Ushahidi in Kenya have been enabled by platforms such as cell phones and social networks. Voices of Africa, based in southern Africa, publishes on the web only. Publishing on the Internet presumes a citizenry which is relatively well educated; has familiarity with, and access to, new media as a form of social communication; and is confident in their right to participate in newly developed public spheres – particularly those online.
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Date Issued: 2017

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Can contracts be both plain and precise?

- Siebörger, Ian, Adendorff, Ralph D

Authors: Siebörger, Ian , Adendorff, Ralph D
Date: 2012
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/123299 , vital:35425 , https://doi.org/10.2989/16073614.2011.651944
Description: One argument against the use of plain language in legal documents is that it is impossible to convey legal meanings in plain language with the same precision as in specialist legal discourse (Hunt, 2003). We tested this claim by redrafting an extract from a lease agreement into plain English in three stages, producing three versions of the extract in progressively plainer English. We submitted these with the original lease agreement to a senior advocate to elicit his opinion on whether the plain-language versions of the extract are equivalent to the original in legal force. Various differences between the versions are analysed using lexical semantics and Systemic Functional Grammar (as described in Halliday & Matthiessen, 2004). This analysis reveals that the redrafted versions could easily be altered to eliminate the difference between them and the original extract, and that ‘plain language’ as conceived by redrafters of official documents may be easy for non-experts to read, but more difficult for experts. This demonstrates that a ‘one-size-fits-all’ approach to readability is often not tenable, and that plain-language activists can learn much from research (such as Street, 1993) which asserts the existence of a plurality of literacies.
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Date Issued: 2012

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A Crown on the Move: stylistic integration of the Luba-Lunda complex in Lunda-Kazembe performance

- Simbao, Ruth K

Authors: Simbao, Ruth K
Date: 2013
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/147524 , vital:38646 , https://doi.org/10.1162/afar.2006.39.3.26
Description: Carried on a scarlet and zebra-hide litter above the heads of a throbbing crowd, Mwata Kazembe XIX gloriously stretches out his arms as if to embrace a world that is his own (Fig. 1). As he parts the sea of well-wishers, splashes of red burst into view and the talking drum beats out its decree. Basking in a charged clamor where the senses blur in clouds of dust, Mwata gracefully sways from side to side, jangling the beads and cowries on the back of his akatasa crown. It is on this day that the Lunda-Kazembe Crown moves.
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Date Issued: 2013

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Versions of hospitality in recent writing on the fiction of JM Coetzee:

- Marais, Mike

Authors: Marais, Mike
Date: 2013
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/144039 , vital:38305 , DOI: 10.4314/eia.v40i1.8
Description: In one of the interviews in Summertime, Martin, a former colleague, claims that he and the deceased John Coetzee felt their "presence" in South Africa "was legal but illegitimate," that it "was grounded in a crime, namely colonial conquest," which rendered them "sojourners, temporary residents, and to that extent without a home, without a homeland" (209-10). With this statement in mind, Maria J. Lopez argues that a sense of unbelonging underlies J. M. Coetzee's entire oeuvre, including the Australian fiction, and forms a kind of "imaginative and intellectual masterplot" (xii). ). It is this "narrative" that she traces in her monograph, starting with the early fiction and concluding with chapters on the fictionalised autobiographies and Australian fiction.
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Date Issued: 2013

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Colonised minds?: post-development theory and the desirability of development in Africa

- Matthews, Sally

Authors: Matthews, Sally
Date: 2017
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/142213 , vital:38059 , DOI: 10.1080/01436597.2017.1279540
Description: While post-development theory is very concerned with the ways in which development has impacted upon the countries of the Global South, there has been relatively little written on post-development theory from an African perspective. This paper identifies some of the ways in which post-development theory fails to adequately understand the African experience of development. In particular, I explore the difficulty that post-development theory confronts when faced with the continued desire on the part of many people in Africa for development.
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Date Issued: 2017

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Ontogenetic and seasonal shifts in the diet of Diplodus cervinus hottentotus (Pisces: Sparidae) in southern Angola

- Winkler, Alexander C, Santos, Carmen V D, Potts, Warren M

Authors: Winkler, Alexander C , Santos, Carmen V D , Potts, Warren M
Date: 2014
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/125452 , vital:35784 , https://doi.10.2989/1814232X.2014.951392
Description: Fishes of the family Sparidae occupy a diverse range of trophic niches, from herbivores to generalist omnivores and specialist predators (Hanel and Tsigenopoulos 2011). Feeding specialisation in this family is facilitated by diversity in tooth type and anterior jaw arrangement (Vandewalle et al. 1995). Other fish families, such as Cyprinidae and Labridae, have developed crushing pharyngeal teeth to process their food. Sparids, however, have retained a simple pharyngeal tooth arrangement and instead have developed molariform teeth to process hard-shelled molluscs and invertebrate prey. Hanel and Tsigenopoulos (2011) suggested that this alternate strategy is a major factor facilitating the trophic diversity in sparid fishes.
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Date Issued: 2014

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The Primacy of Effective Human Capital Management to the Growth of Entrepreneurship Ventures. A Study of Cases from the Fast Food Restaurant Sector in Cape Town

- Asoba, Samson Nambei, Patricia, Nteboheng Mefi

Authors: Asoba, Samson Nambei , Patricia, Nteboheng Mefi
Date: 2021
Subjects: Entrepreneurship Human capital Article
Language: English
Type: text , article
Identifier: http://hdl.handle.net/11260/8135 , vital:61400 , xlink:href="https://www.abacademies.org/articles/the-primacy-of-effective-human-capital-management-to-the-growth-of-entrepreneurship-ventures-a-study-of-cases-from-the-fast-food-r-10259.html"
Description: This paper draws on two fields, human resources management and entrepreneurship to examine the observed problem of stalled established business ownership even despite favourable Total Early Stage entrepreneurship (TEA) among many nations. The aim of the study was to established the perceptions of entrepreneurs on the influence of human capital on the growth and sustainability of entrepreneurial ventures from the restaurant sector in Cape Town. The study adopted a qualitative research design which was based on interviews to infer the entrepreneurs’ perceptions on the role of effective human capital management to growth of entrepreneurial ventures. Fifteen interviews were conducted and analysed following a thematic analyse procedure. Various themes and sub themes which pointed to the critically of effective human capital management were established. It was found the people possess certain social, philosophical, psychological and ideological attributes that cannot be found from other resources. At the end of the analysis, it was established that human resources are central to the growth of entrepreneurial ventures as they possess certain exploitable entrepreneurial talents, are capable of unlocking the value of other resources and also they are the drivers of growth. Following these findings, it was recommended that entrepreneurs should centralise effective human capital management for growth. Keywords: Entrepreneurship, Human Capital, Small Businesses, Business Growth, Competitive Advantage
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Date Issued: 2021

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Optical limiting properties of zinc phthalocyanines in solution and solid PMMA composite films

- Tekin, Sezen, Kürüm, Ulaş, Durmus, Mahmut, Yaglioglu, H Gul, Nyokong, Tebello, Elmali, Ayhan

Authors: Tekin, Sezen , Kürüm, Ulaş , Durmus, Mahmut , Yaglioglu, H Gul , Nyokong, Tebello , Elmali, Ayhan
Date: 2010
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/249071 , vital:51775 , xlink:href="https://doi.org/10.1016/j.optcom.2010.07.003"
Description: The nonlinear absorption and optical limiting (OL) performance of tetra- and octasubstituted zinc phthalocyanine complexes were described in solution and in the solid state using the open-aperture Z-scan technique. The measurements were performed using collimated 4 ns pulses generated from a frequency-doubled Nd:YAG laser at 532 nm wavelength. The polymeric films exhibit a much larger effective nonlinear absorption coefficient in comparison with solution. However, the parameters of the ratio of the excited to ground state absorption cross section and energy-dependent saturation in solution are much better compared to properties in the polymeric film. In terms of the ratio of the excited to ground state absorption cross section, the peripherally substituted complexes show better OL performance than the non-peripherally substituted derivative.
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Date Issued: 2010

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