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Reaction of Perrhenate with Phthalocyanine Derivatives in the Presence of Reducing Agents and Rhenium Oxide Nanoparticles in Biomedical Applications

  • Authors: Ntsimango, Songeziwe , Gandidzanwa, Sendibitiyosi , Joseph, Sinelizwi V , Hosten, Eric C , Randall, Marvin , Edkins, Adrienne L , Khene, Samson M , Mashazi, Philani N , Nyokong, Tebello , Abrahams, Abubak’r , Tshentu, Zenixole R
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/300257 , vital:57910 , xlink:href="https://doi.org/10.1002/open.202200037"
  • Description: A novel alternative route to access rhenium(V)−phthalocyanine complexes through direct metalation of metal-free phthalocyanines (H2Pcs) with a rhenium(VII) salt in the presence of various two-electron reducing agents is presented. Direct ion metalation of tetraamino- or tetranitrophthalocyanine with perrhenate (ReO4−) in the presence of triphenylphosphine led to oxidative decomposition of the H2Pcs, giving their respective phthalonitriles. Conversely, treatment of H2Pcs with ReO4− employing sodium metabisulfite yielded the desired ReVO−Pc complex. Finally, reaction of H2Pcs with ReO4− and NaBH4 as reducing agent led to the formation of rhenium oxide (RexOy) nanoparticles (NPs). The NP synthesis was optimised, and the RexOy NPs were capped with folic acid (FA) conjugated with tetraaminophthalocyanine (TAPc) to enhance their cancer cell targeting ability. The cytotoxicity profile of the resultant RexOy−TAPc−FA NPs was assessed and found to be greater than 80 % viability in four cell lines, namely, MDA−MB-231, HCC7, HCC1806 and HEK293T. Non-cytotoxic concentrations were determined and employed in cancer cell localization studies. The particle size effect on localization of NPs was also investigated using confocal fluorescence and transmission electron microscopy. The smaller NPs (≈10 nm) were found to exhibit stronger fluorescence properties than the ≈50 nm NPs and exhibited better cell localization ability than the ≈50 nm NPs.
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  • Date Issued: 2022

Refining youth sexualities empowerment programmes: The development of the Masizixhobise Toolkit based on a critical sexual and reproductive citizenship framework

  • Authors: Macleod, Catriona I , Moore, Sarah
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , book chapter
  • Identifier: http://hdl.handle.net/10962/434158 , vital:73035 , ISBN 9781003139782 , https://www.taylorfrancis.com/chapters/edit/10.4324/9781003139782-15/refining-youth-sexualities-empowerment-programmes-catriona-ida-macleod-sarah-moore
  • Description: Youth sexualities programmes frequently focus on empowering young people in relation to sexual decision-making and interactions. Within these programmes, however, empowerment is mostly equated with the individualised concepts of self-efficacy and agency to the exclusion of interpersonal and social (i.e. collective) components. Resultantly, the social justice aspects of empowerment may be overlooked. Noting this, some researchers have argued for the adoption of a broader, integrative conceptualisation of empowerment. Macleod’s and Vincent’s critical sexual and reproductive citizenship (CSRC) framework provides such a conceptualisation. This framework draws from feminist re-workings of the principles of citizenship and applies these to understandings of CSRC. Based on this framework, key issues for consideration in programmes are: sexual and reproductive citizenship as status and practice; situated agency; differentiated universalism; the interweaving of the private and public; and the politics of recognition, redistribution and reparation. This chapter discusses the development of a programme refinement toolkit based on a CSRC framework, named the Masizixhobise Toolkit; how the elements outlined above were operationalised into questions; an illustrative example; and the partnership formed with a youth empowerment non-governmental organisation in developing the toolkit.
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  • Date Issued: 2022

Reflections from early-career researchers on the past, present and future of doctoral education

  • Authors: Mason, Shannon , Lévesque, Maude , Meki-Kombe, Charity , Abel, Sophie , Balaban, Corina , Chiappa, Roxana , Grund, Martin , Joubert, Biandri , Kuchumova, Gulfiya , Mantai, Lilia , Main, Joyce , Motshoane, Puleng , Qi, Jing , Steyn, Ronel , Zheng, Gaoming
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , book chapter
  • Identifier: http://hdl.handle.net/10962/434543 , vital:73075 , ISBN 9781800080218 , https://library.oapen.org/bitstream/handle/20.500.12657/58197/1/9781800080188.pdf#page=264
  • Description: Early-career researchers (ECRs) played a unique and explicit role in the development of the Hannover Recommendations 2019. We, the ECRs, were the recipients of competitive travel scholarships generously funded by Volkswagen Stiftung, whose support brought us together from across the globe. Attendance at the culminating conference in Germany presented an opportunity for some that would have otherwise been inaccessible without that support. Our role was to work alongside established scholars to design and develop a set of recommendations to provide a foundation for the future of doctoral education internationally. We each participated in different capacities, with some members of the group joining preliminary pre-conference online meetings and contributing to group discussions at the workshop in the days prior to the conference, which also involved the drafting of written reports. Others joined later in the process, participating in the discussions that were a central part of the conference proceedings. During the events we also had informal opportunities to discuss issues related to various aspects of doctoral education. Although we participated in varying degrees and contexts, we each contributed to discussions on the current status and future directions of doctoral education globally.
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  • Date Issued: 2022

Situating the diversity of Southern African environmental education scholarship within a global conversation at a critical juncture on Earth

  • Authors: Olvitt, Lausanne L
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/389869 , vital:68491 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/247386"
  • Description: ¬The collection of papers in Volume 38 in many ways mirrors the diversity of research methodologies and teaching approaches in the contemporary eld of Environmental and Sustainability Education. ¬ e seven papers remind us that, whilst environmental educators and researchers are largely in agreement over the nature and causes of the social-ecological problems that we face in sub-Saharan Africa, there is less certainty around what types of educational approaches and pedagogies are adequate to help resolve them. ¬ e papers in this volume either o er pedagogical innovations that may strengthen teaching and learning for sustainable futures, or they provide insights into the social, cultural and economic contexts in which such teaching and learning occurs.
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  • Date Issued: 2022

Small but strong: Socioeconomic and ecological resilience of a small European fishing community affected by a submarine volcanic eruption

  • Authors: De la Cruz-Modino, Raquel , Piñeiro-Corbeira, Cristina , Gutiérrez-Barroso, Josué , González-Cruz, Carla , Barreiro, Rodolfo , Batista-Medina, José A , Pascual-Fernández, José , González, José A , Santana-Talavera, Agustín , Aswani, Shankar
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/391397 , vital:68648 , xlink:href="https://doi.org/10.1016/j.ocecoaman.2022.106124"
  • Description: Small-scale coastal fishing communities are facing many new challenges, such as rapid ecological changes created by anthropogenic and natural events like earthquakes or volcanic eruptions. This paper explores how a coastal population has responded to such an event and highlights the diverse coping strategies used to tackle it. This research was conducted on the island of El Hierro (Spain), where a submarine volcanic eruption occurred in 2011, affecting a multiple-use Marine Protected Area (MPA) and the nearby fishing community of La Restinga. Our study illustrates how the local population coped with this situation by combining multiple monetary and non-monetary activities (e.g., informal exchanges) as well as the role of institutions in increasing local resilience by supporting fishers' demands and allowing their participation in the decision-making process in the immediate wake of a catastrophic event. Local families also exploited various natural resources in and near the MPA, thus ensuring access to crucial marine resources and continued recreational/cultural services. The results suggest that collective action played a key role in the recovery process after the eruption, creating some advantages for different local groups despite the hazardous nature of the event.
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  • Date Issued: 2022

Sn (IV) porphyrin-biotin decorated nitrogen doped graphene quantum dots nanohybrids for photodynamic therapy

  • Authors: Magaela, N Bridged , Matshitse, Refilwe , Balaji, Babu , Managa, Muthumuni , Prinsloo, Earl , Nyokong, Tebello
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/230018 , vital:49733 , xlink:href="https://doi.org/10.1016/j.poly.2021.115624"
  • Description: Photodynamic therapy (PDT) is a minimally invasive therapeutic procedure for cancer treatment. This study focuses on the synthesis, photophysicochemical properties, and PDT activity of Sn (IV) porphyrin (2), when linked to biotin decorated nitrogen doped graphene quantum dots (B-NGQDs). The porphyrin complex 2 was conjugated through an ester bond to B-NGQDs to form 2-B-NGQDs. Singlet oxygen quantum yield increased for 2 when linked to B-NGQDs to form 2-B-NQGDs. The dark toxicity and photodynamic therapy studies were conducted for 2, NGQDs and their conjugates using MCF-7 breast cancer cells. The cell viability for dark toxicity of all the compounds was above 90%, and 2-B-NGQDs showed high PDT activity at a concentration of 40 µg/mL with cell viability of 22%.
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  • Date Issued: 2022

Social, ethical and cultural responsibility as core values for doctoral researchers in the 21st century

  • Authors: Chiappa, Roxana , Cantini, Danielle , Karakasoglu, Yasemin , Manathunga, Catherine , Peters, Christian , Scholz, Beate , Yarar, Betul
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , book chapter
  • Identifier: http://hdl.handle.net/10962/434515 , vital:73072 , ISBN 9781800080218 , 10.14324/111.9781800080188
  • Description: With the dramatic events of a global pandemic, the beginning of the twenty-first century’s third decade has underlined that the world is facing universal challenges. The worldwide crisis scenario that COVID-19 has produced makes us realise that science and research do not function and operate in an independent sphere hidden within the proverbial ivory tower, but, on the contrary, are closely linked to the social, cultural and political systems they reside in. This creates opportunities and great tensions and, while exploring those, Chapter 9 connects to and builds on most of the dimensions described in the previous sections of the book. We refer primarily to Hannover Recommendations 1 and 7: 1. Establish a global joint value system for doctoral education based on an ecology of knowledges which recognises and seeks to overcome existing inequalities in the access to doctoral education and the provision of knowledge. 7. The pivotal goal of doctoral education must be and remain the development of original, responsible, and ethical thinkers, and the generation of new and original ideas and knowledge.
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  • Date Issued: 2022

Social-ecological change: insights from the Southern African Program on Ecosystem Change and Society

Socio-ecological Justice Informed Curriculum: Inquiry Transformative Potentials of Critical Water Pedagogy

  • Authors: James, Anna
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , book chapter
  • Identifier: http://hdl.handle.net/10962/436159 , vital:73231 , ISBN 978-3-030-84510-0 , https://doi.org/10.1007/978-3-030-84510-0_5
  • Description: This paper brings water education, critical pedagogy, and environmental learning into dialogue for the purposes of ar-ticulating some tensions and openings toward a critical envi-ronmental pedagogy that is asked of us in contexts of the Global South. Against this backdrop, I present a pedagogical framework for a socio-ecological school’s audit which seeks to bring to life the possibility of merging environmental and social movement knowledge. Drawing on the threads of transformative potential from literature on water education projects situated in South Africa, I offer a framework for en-gaging with water as socio-ecological phenomena that re-spond to multiple experiences and the urgency of knowing and shifting our structural relationship to water.
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  • Date Issued: 2022

South African Lagerstätte reveals middle Permian Gondwanan lakeshore ecosystem in exquisite detail

  • Authors: Prevec, Rosemary , Nel, André , O.Day, Michael , Muir, Robert , Matiwane, Aviwe , Kirkaldy, Abigail P , Moyo, Sydney , Staniczek, Arnold , Cariglino, Bárbara , Maseko, Zolile , Kom, Nokuthula , Rubidge, Bruce S , Garrouste, Romain , Holland, Alexandra J , Barber-James, Helen M
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/426673 , vital:72378 , xlink:href="https://doi.org/10.1038/s42003-022-04132-y"
  • Description: Continental ecosystems of the middle Permian Period (273–259 million years ago) are poorly understood. In South Africa, the vertebrate fossil record is well documented for this time interval, but the plants and insects are virtually unknown, and are rare globally. This scarcity of data has hampered studies of the evolution and diversification of life, and has precluded detailed reconstructions and analyses of ecosystems of this critical period in Earth’s history. Here we introduce a new locality in the southern Karoo Basin that is producing exceptionally well-preserved and abundant fossils of novel freshwater and terrestrial insects, arachnids, and plants. Within a robust regional geochronological, geological and biostratigraphic context, this Konservat- and Konzentrat-Lagerstätte offers a unique opportunity for the study and reconstruction of a southern Gondwanan deltaic ecosystem that thrived 266–268 million years ago, and will serve as a high-resolution ecological baseline towards a better understanding of Permian extinction events.
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  • Date Issued: 2022

Stereotyping, Exploitation, and Appropriation of African Traditional Religious Beliefs: The Case of Nyaminyami, Water Spirit, among the Batonga People of Northwestern Zimbabwe, 1860s–1960s

  • Authors: Matanzima, Joshua
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/426543 , vital:72361 , xlink:href="https://doi.org/10.5325/jafrireli.10.1.0072"
  • Description: This article examines the forms of knowledge that existed between Africans and Europeans regarding local indigenous religious beliefs, focusing particularly on the case of Nyaminyami, a water spirit that is part of the belief systems prevalent among some BaTonga people of northwestern Zimbabwe. The article briefly outlines the “traditional” BaTonga beliefs and practices relating to Nyaminyami, which were diametrically opposed to those of the Europeans. It then scrutinizes the ways the beliefs have been exploited and appropriated by different interest groups and races from the 1860s to the 1960s. The BaTonga people, who held strong beliefs in Nyaminyami, and European colonists used the idea of Nyaminyami for different social, political, and environmental agendas prior to, during, and after resettlement. Nyaminyami played changing sociocultural and economic functions for the BaTonga people over time. They revered Nyaminyami as their river god in the nineteenth and twentieth centuries; they also appropriated the beliefs by rallying behind the river god for protection from their displacement in 1958 following the construction of the Kariba Dam on the Zambezi River. Nyaminyami was also appropriated by European interest groups who used the idea of Nyaminyami to cast Africa as the “dark continent” and to stereotype the BaTonga people as primitive. This article relies on data obtained through a reading of European explorers' texts and by gathering oral traditions among the BaTonga and Shangwe.
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  • Date Issued: 2022

Structural modification of RhIIItriarylcorroles for enhanced electrocatalyzed hydrogen evolution reactions

  • Authors: Zhu, Weihua , Li, Lihua , Wang, Yu , Mack, John , Dingiswayo, Somila , Nyokong, Tebello , Liang, Xu
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/229933 , vital:49724 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.110046"
  • Description: A series of A3 type RhIIItriarylcorroles 2a-c with different meso-substituents with differing electron-donating and withdrawing properties and two A2B type RhIIItriarylcorroles 4a-b with meso-methylthiophenyls at the B position have been prepared and characterized. An analysis of structure-property relationships of 2a-c and 4a-b has been carried out by comparing the optical spectroscopy and electrochemistry of the dyes to trends predicted in DFT and TD-DFT calculations. Rational structural modification strategies that enhance the suitability of 2a-c for use as highly efficient catalysts for hydrogen evolution reactions on glassy carbon electrodes coated with 2a-c/reduced graphene oxide composites and of 4a-b in surface-modified Au electrodes are explored.
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  • Date Issued: 2022

Suitably Strange: Re-imagining learning, scholar-activism, and justice

  • Authors: McGarry, Dylan K
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/371005 , vital:66402 , xlink:href="https://hdl.handle.net/10520/ejc-cristal-v10-n1-a7"
  • Description: Using artworks emergent from my career as a pracademic and scholar activist, I attempt to share a ‘tactile theory’ of being and doing, that refer mainly to response-abilities (i.e., abilities to respond in accountable ways) in scholar activist educational sociology. I aim to make visible (and tactile) the sometimes-invisible qualities and practices needed for navigating the eroded and dying ecological relations of our generation, as well as warming up and making pliable the heteronormative, capitalist, patriarchal and anthropocentric conventions that are associated with it. In order to warm and sculpt these normative conventions, I argue for the need for ‘suitably strange’ practice. I present six images and associated prose that aim to optimally disrupt these conventions, towards generative rethinking and embodying learning, scholar activism and justice, and from which I explore a tactile theory, an example and related response-ability for each. I end with a reflection of how these suitably strange artefacts can help us develop a new concept of proactive-cognitive justice or ‘justness’.
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  • Date Issued: 2022

Symmetry effect of cobalt phthalocyanines on the aluminium corrosion inhibition in hydrochloric acid

  • Authors: Nnaji, Nnaemeka , Sen, Pinar , Nyokong, Tebello
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/231323 , vital:49877 , xlink:href="https://doi.org/10.1016/j.matlet.2021.130892"
  • Description: The aluminium corrosion retardation potentials of phthalocyanine-based dyes, cobalt (II) 2,9,16-tris(4-(tert-butyl)phenoxy)-23-(pyridin-4-yloxy)phthalocyanine (D1) and cobalt (II) 2,9,16,24-tetrakis(4-(tert-butyl)phenoxy)phthalocyanine (D2) in 1 M hydrochloric acid were evaluated. Results from potentiodynamic polarization measurements show that inhibition efficiency increased with inhibitor concentration at 28 °C with values of 91.9 % and 87.0 % values respectively for D1 and D2 at 10 μM.
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  • Date Issued: 2022

Synergistic recognition and electrochemical sensing of 17β-Estradiol using ordered molecularly imprinted polymer-graphene oxide-silver nanoparticles composite films

  • Authors: Regasa, Melkamu Biyana , Nyokong, Tebello
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/295829 , vital:57382 , xlink:href="https://doi.org/10.1016/j.jelechem.2022.116713"
  • Description: Synthetic molecularly imprinted polymers (MIPs) based functional materials become the best alternatives to alleviate the stability and cost issues related to biological receptors commonly used in biochemical sensors. To address this demand, we report the development of a highly selective and sensitive MIPs-based electrochemical sensor for the detection of 17β-estradiol (E2). The sensor was prepared based on the MIP-graphene oxide (GO)-silver nanoparticle (AgNP) nanocomposite functional materials electrodeposited on the surface of the glassy carbon electrode (GCE). At first, AgNp formation was facilitated by using ascorbic acid to reduce and stabilize it. A very stable MIP-GO-AgNP sensing layer with multifunctional units were formed using imidazole as a functional monomer (p-type-electron acceptor), GO (n-type-electron donor), and AgNP by using the electrodeposition method. The role of GO in the system is providing additional functional units to bind the template and improve materials morphology while that of AgNPs is acting as a catalyst and charge carrier. The characterization of the sensing materials was done by using Fourier transform infrared, scanning electron microscopy, energy dispersive X-ray spectroscopy, and cyclic voltammetry. After optimization of the essential parameters, the sensor was successfully applied to detect the target analyte using the square wave voltammetric technique. The prepared sensor exhibited a wide linear range of 10 fM-250 nM with the limit of detection and limit of quantification of 3.01 fM and 10.03 fM, respectively. The high percentage recoveries, sensitivity, repeatability, and easy fabrication of the MIP-GO-AgNP materials made the proposed sensor promising for environmental monitoring applications in the future.
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  • Date Issued: 2022

Systematic review of genome-wide association studies of anxiety disorders and neuroticism

  • Authors: Van Der Walt, Kristien , Campbell, Megan , Stein, Dan J , Dalvie, Shareefa
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/302532 , vital:58205 , xlink:href="https://doi.org//10.1080/15622975.2022.2099970"
  • Description: Objectives: To summarise SNP associations identified by genome-wide association studies (GWASs) of anxiety disorders and neuroticism; to appraise the quality of individual studies, and to assess the ancestral diversity of study participants. Methods: We searched PubMed, Scopus, PsychInfo and PubPsych for GWASs of anxiety disorders, non-diagnostic traits (such as anxiety sensitivity), and neuroticism, and extracted all SNPs that surpassed genome-wide significance. We graded study quality using Q-genie scores and reviewed the ancestral diversity of included participants. Results: 32 studies met our inclusion criteria. A total of 563 independent significant variants were identified, of which 29 were replicated nominally in independent samples, and 3 were replicated significantly. The studies had good global quality, but many smaller studies were underpowered. Phenotypic heterogeneity for anxiety (and less so for neuroticism) seemed to reflect the complexity of capturing this trait. Ancestral diversity was poor, with 70% of studies including only populations of European ancestry. Conclusion: The functionality of genes identified by GWASs of anxiety and neuroticism deserves further investigation. Future GWASs should have larger sample sizes, more rigorous phenotyping and include more ancestrally diverse population groups.
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  • Date Issued: 2022

The (Slow) Urgency of Socio-cological Justice in ESE–Listening to Children in Marginalized Positions in ESE

  • Authors: Jørgensen, Nanna J , James, Anna
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , book chapter
  • Identifier: http://hdl.handle.net/10962/437526 , vital:73391 , ISBN
  • Description: As a contribution to discussions about how ESE research respond to increasing urgency and climate emergencies, this essay discusses the relation between education and the pursuit of societal transformation with a view to questions of socio-ecological justice. Our research interest centers on young children’s participation and voice, on the inequalities which constitute barriers to this participation, and on the potentials of a more fine-tuned pedagogy which listens to children’s voices and their relations with the non-human environment in our research practices. This listening is a radical process of unlearning and rethinking ‘urgency’. The essay is based on an ongoing dialogue about how research on sustainability education might respond to the voices of children in marginalized positions across two very different geographical and socio-cultural settings–the Danish welfare state and post-apartheid South Africa (see James and Jørgensen, forthcoming). Here we draw attention to the dangers of assumptions underlying urgency (dualism and instrumentalism) and the voices of young children in research as a practice that resists these dangers.
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  • Date Issued: 2022

The contribution of wild palms to the livelihoods and diversification of rural households in southern Mozambique

  • Authors: King, Angelina R , Shackleton, Charlie M
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/399846 , vital:69563 , xlink:href="https://doi.org/10.1016/j.forpol.2022.102793"
  • Description: In most low-income countries, rural households combine a range of economic activities to generate income, achieve food and nutritional security and fulfill other livelihood objectives, including: small-scale farming, fishing, hunting, livestock and timber production, and non-timber forest products gathering, as well as off-farm activities such as wage labour and informal trading. This work examines the role of diversification, including palm products income, on rural livelihoods in the Zitundo area, southern Mozambique. Seven livelihood strategies were identified, with every strategy combining cash income from several sources. Most households adopt a wage-based strategy to some degree, although this strategy shows low potential for reducing poverty in the area. Households adopting a palm-based strategy show between 23% and 60% lower poverty incidence than those adopting alternatives strategies. Yet, a palm-based livelihood strategy was adopted by only 11% of households. Traders of palm products earn approximately double the annual income and per capita income than non-traders. Village of residency and some household socio-economic and demographic characteristics correlate with a households' choice of livelihood strategy and palm income dependency. The adherence of many households to a less remunerative wage strategy indicates other factors also influence the choice of livelihood strategies. The study shows that future development plans and policy interventions to mitigate poverty in the area should go beyond the usual agricultural sector and recognize the role of non-timber forest products, especially palm products, for people's livelihoods and poverty alleviation.
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  • Date Issued: 2022

The effect of charge on Zn tetra morpholine porphyrin conjugated to folic acid-nitrogen doped graphene quantum dots for photodynamic therapy studies

  • Authors: Magaela, N Bridged , Matshitse, Refilwe , Nyokong, Tebello
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/295840 , vital:57383 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.102898"
  • Description: Zinc tetra morpholine porphyrin (complex 2), and its quaternized derivative (complex 3) were synthesized and conjugated to folic acid decorated nitrogen doped graphene quantum dots (FA-NGQDs) through π−π stacking to study their photodynamic therapy (PDT) efficacy. Photophysiochemical properties of complexes 2, 3, and their conjugates (2-FA-NGQDs, 3-FA-NGQDs) were studied. It was found that complex 3 had higher ϕΔ of 0.56 compared to complex 2 with ϕΔ of 0.24, and respective composites: 3-FA-NGQDs had higher ϕΔ compared to 2-FA-NGQDs. The PDT studies were conducted for nanoparticles (FA-NGQDs), complexes (2, 3), and respective composites (2-FA-NGQDs, and 3-FA-NGQDs) using MCF-7 breast cancer cell. Dark toxicity of all compounds was above 90% which is negligible. At a highest concentration of 40 µg/mL, 3-FA-NGQDs gave the lowest cell viability of 28% compared to all other conjugates and porphyrins alone.
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  • Date Issued: 2022

The Electrocatalytic Detection of Nitrite Using Manganese Schiff Base Phthalocyanine Complexes

  • Authors: Ndebele, Nobuhle , Nyokong, Tebello
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/295856 , vital:57385 , xlink:href="https://doi.org/10.1007/s12678-022-00752-4"
  • Description: This work investigates the use of manganese phthalocyanines (MnPcs) in the electrochemical detection of nitrite. These are two Schiff base derivatives: tetrakis 4-(4-thio-thiophene-2-ylmethanamino) phthalocyaninato Mn(III)Cl (2) and tetrakis 4-(3-(pyrrolidine-1-yl)propan-1-amino)phthalocyaninato Mn(III)Cl (3) and one aldehyde: tetrakis(4-formylphenoxy)phthalocyaninato Mn(III)Cl (1). The MnPc complexes were adsorbed onto the glassy carbon electrode surface using the drop-dry method and used as electrocatalysts to detect nitrite. Nitrite oxidation peak potentials obtained using cyclic voltammetry ranged between 0.70 and 0.84 V. Detection limits as low as 0.16 µM and sensitivity values as high as 276 µMmM−1 were obtained through the use of chronoamperometry. The Schiff base MnPcs 2 and 3 exhibited better nitrite detection properties (in terms of limit of detection and sensitivity) than their aldehyde precursor (1).
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  • Date Issued: 2022
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